Basic Firearms Course Section 5 Page : Basic Shooting Techniques

OK! Did you skip forward to start with this section? - Shame- Shame on you,get back to Section 1 and go thru it all. If you are one of the few who didn't jump the gun ( no pun intended) , never mind please continue.

You've finally gone thru all the ground work to get yourself to this point, you are now ready to learn the basic techniques for proper handgun use.There are five essentials to learn in order to properly and accurately shoot a handgun:PositionGripBreath ControlSight AlignmentTrigger SqueezeFollow Through

Position: Proper alignment of your body and handgun with the target.Grip: Keep the handgun pointed in a safe direction and shake hands with the grip of the handgun, fitting the "V' formed by the thumb and index finger of the shooting hand as high as possible on the backstrap ( back of the grip). Remember to keep your finger off the trigger (start getting in the habit now to keep your trigger finger along the frame just above the trigger/ trigger guard. Next you will use your weak hand to grip finish your grip. I won't take the time to explain this part - Our instructors will explain and demonstrate the grip to each student and make adjustments as you shoot.Breath Control: Breath control is required to minimize body movement which in turn reduces handgun movement. For target shooting it is recommended that you take a breath between shots - let out enough air to be comfortable and then shoot. Now for self-defense or tactical situations you will later need to learn to control your breathing while performing tactical movement and shooting. Ninja Stuff, Cool! That comes in later classes.Sight Alignment: Proper sight alignment is the relationship of the front and rear sights. To

properly align the two sights the top of the front sight is even with the top of the rear sight - the front sight must be centered in the notch of the rear sight (see illustration). Proper sight alignment is key to accurate shooting. Any misalignment of the front sight with the rear sight will cause inaccuracies of your shot placement. Our instructors will work with you during the range time to further discuss and demonstrate proper sight alignment. You will aim with your dominant eye when shooting a handgun. Just because you are right handed it does not mean that you are right eyed dominant. Our instructors will show you a easy test to determine your dominant eye. Trigger Squeeze: Trigger squeeze is exactly that, you squeeze the trigger back in order to shoot the handgun - you do not pull or jerk the trigger back. The trigger must be squeezed straight back in a smooth continuous motion. Follow Through: Continuing to apply all of the shooting fundamentals throughout the delivery of the shot. Trigger Squeeze and sight alignment are considered to be the two most important factors in accurate shooting The other four fundamentals all combine to assist in achieving proper sight alignment and trigger squeeze. All the fundamentals must be properly performed every time in order to shoot the pistol accurately.

Iron sightFrom Wikipedia, the free encyclopediaJump to: navigation, search

Sight picture through iron sights of an H&K MP5 submachine gun. The annular shroud around the front post sight is aligned with the rear peep sight to ensure the weapon is properly trained.Iron sights are a system of shaped alignment markers (usually metal) used as a sighting device to assist in the aiming of a device such as a firearm, crossbow, or telescope, and exclude the use of optics as in telescopic sights or reflector (reflex) sights.[1] Iron sights are typically composed of two component sights, formed by metal blades: a rear sight mounted perpendicular to the line of sight and consisting of some form of notch (open sight) or aperture (closed sight); and a front sight that is a post, bead, or ring. Civilian defensive, hunting, and police firearms usually feature open sights, while many military battle rifles employ aperture sights. On many firearms the rear sight is adjustable for elevation or windage.[2]The earliest and simplest iron sights are fixed and cannot be easily adjusted. Many iron sights are designed to be adjustable, so that the sights can be adjusted for windage and elevation. For precision applications such as hunting or sniping the iron sights are usually replaced by a telescopic sight. Iron Sights may still be fitted alongside a telescopic sight and are referred to as Back Up Iron Sights (Acronym B.U.I.S).Contents[hide]1 Theory2 Fixed sights3 Adjustable sights4 Types of sights 4.1 Open sights 4.1.1 Advantages and disadvantages4.2 Aperture sights 4.2.1 Ghost rings4.2.2 Target aperture sights4.3 Shotgun beads5 Enhancements 5.1 Glare reduction5.2 Fixed vs. adjustable sights5.3 Contrast enhancements5.4 Concealed carry6 Optical sights7 Adjusting for accuracy8 See also9 References 9.1 Notes10 External links

[edit] Theory

A sight picture with focus on the front sight; the out of focus gray dot represents the targetIn the case of firearms, where the bullet follows a Newtonian trajectory, front and rear sights must be aligned with the line of sight of the shooter, calibrated to the distance of the target and the trajectory of the bullet, so that the bullet hits the target. Iron sights provide horizontal and vertical reference points that allow the shooter to train the weapon.[2]Rear sights are usually mounted in a dovetail on the barrel or receiver, closer to the eye of the shooter, allowing for easy visual pick-up of the notch. Front sights are mounted to the barrel by dovetailing, sweat soldering, screwing, or staking close to the muzzle, frequently on a ramp. Some front sight assemblies include a detachable hood intended to reduce glare.[2]With typical blade iron sights, the shooter should center the front post in the notch of the rear sight and the tops of both sights should be level.[2] Since the eye is only capable of focusing on one plane, and the rear sight, front sight, and target are all in separate planes, only one of those three planes can be in focus. Which plane is in focus depends on the type of sight, and one of the challenges to a shooter is to keep the focus on the correct plane to allow for best sight alignment. For a more in-depth look at the relationship between sight alignment and where a bullet will hit, see here: Getting a Sight PictureEven a tiny error in the angle of sight alignment results in a trajectory that diverges from the target on a trajectory directly relative to the distance from the target, causing the bullet to miss the target; for example with an Olympic 10 metre air rifle shooter trying to hit the 10 ring, which is merely a 0.5mm diameter dot on the target at 10 meters and with a 4.5mm diameter pellet, an error of only 0.2mm in sight alignment can mean a complete miss (a 3mm point of impact miss). At 1,000 meters, that same 0.2mm misalignment would be magnified 100 times, giving an error of over 300mm (1500 times the sight misalignment of 0.2mm). (Calculations assume a 660mm sight radius or sighting line) A long sighting line helps to reduce eventual angle errors and will, in case the sight has an incremental adjustment mechanism, adjust in smaller increments when compared to a further identical shorter sighting line.Sights for shotguns used for shooting small, moving targets (wing shooting or clay shooting) work quite differently. The rear sight is completely discarded, and the rear reference point is provided by the correct and consistent positioning of the shooter's head. A brightly colored (generally brass or silver colored, white, or a fluorescent shade) round bead is placed at the end of the barrel. Often this bead will be placed along a raised, flat rib, which is usually ventilated to keep it cool and reduce mirage effects from a hot barrel. Rather than being aimed like a rifle or handgun, the shotgun is pointedthe focus is always on the target, and the unfocused image of the barrel and bead are placed below the target (the amount below depends on whether the target is rising or falling) and slightly ahead of the target if there is lateral movement. This method of aiming is not as precise as that of a front sight/rear sight combination, but it is much faster, and the wide spread of shot allows a hit even if there is some error in aim. Some shotguns also provide a mid-bead, which is a smaller bead located halfway down the rib, which allows more feedback on barrel alignment.[edit] Fixed sightsThe earliest and simplest iron sights are fixed and cannot be easily adjusted for variables such as target distance, the effect of wind, or variations between different cartridges. For instance, on many revolvers, the rear sight consists of a groove milled into the top of the gun's receiver. However, many supposedly "non-adjustable" sights can actually be adjusted, for example the rear sight can often be drifted to compensate for windage if it is mounted in a dovetail,[2] or the rear sight or channel mentioned above can be filed on one side to alter its alignment with the front sight. In other cases the front sight can be very carefully bent to offset it to one side, filed down, or the blade can be replaced with one of a different height. Any of the aforementioned techniques will result in a successful change to the firearm's point of impact, however in taxing situations such as these the services of a professional gunsmith would be well advised.[3][edit] Adjustable sights

A tangent sight on a CZ 452 rimfire rifle, with calibrated markings for ranges out to 300 metersMany iron sights are designed to be adjustable, so that the sights can be adjusted for windage and elevation. In addition, adjustable sights allow compensation for varying cartridge bullet weights or propellant loadings, which alter the round's velocity and external ballistics and thus its trajectory and point of impact.Sight adjustments are orthogonal, so the windage can be adjusted without impacting the elevation, and vice versa. If the firearm is held canted instead of level when fired, the adjustments are no longer orthogonal, so it is essential to keep the firearm level for best accuracy.The most common is a rear sight that adjusts in both directions, though military rifles often have a tangent sight in the rear, which a slider on the rear sight has pre-calibrated elevation adjustments for different ranges. With tangent sights, the rear sight is often used to adjust the elevation, and the front the windage. The M16A2 later M16 series rifles have a dial adjustable range calibrated rear sight, and use an elevation adjustable front sight to "zero" the rifle at a given range. The rear sight is used for windage adjustment and to change the zero range.[edit] Types of sightsIron sights are broken into two basic categories that include most types. Open sights use a notch of some sort as the rear sight, while aperture sights use a circular hole. Wing and clay-shooting shotgun sights are called shotgun beads, or simply beads.

A selection of open sights, and one aperture sight suitable for use with long eye relief: A) U-notch and post, B) Patridge, C) V-notch and post, D) Express, E) U-notch and bead, F) V-notch and bead, G) trapezoid, H) ghost ring. The gray dot represents the target.[edit] Open sightsOpen sights generally are used where the rear sight is at significant distance from the shooter's eye. They provide minimum occlusion of the shooter's view, but at the expense of precision. Open sights generally use either a square post or a bead on a post for a front sight. The post or bead is placed in the rear sight notch, and the target is placed above and centered on the aligned sights. From the shooter's point of view, there should be a noticeable space between each side of the front sight and the edges of the notch; the spaces are called light bars, and the brightness of the light bars provides the shooter feedback as to the alignment of the post in the notch. Vertical alignment is done by lining up the top of the front post with the top of the rear sight, or by placing the bead just above the bottom of the V or U-notch. If the post is not centered in the V or U notch, the shot will not be accurate. If the post extends over the V or U-notch it will result in a high shot. If the post does not reach the top of the V or U-notch it will result in a low shot.Patridge sights consisting of a square or rectangular post and a flat-bottomed square notch are the most common form of open sights and are preferred for target shooting, as the majority of shooters find the vertical alignment is more precise than other open sights. V-notch and U-notch sights are a variant of the patridge which substitute a 'V' or 'U' shaped rear notch.[2]Other common open sight types include the buckhorn, semi-buckhorn, and express. Buckhorn sights have extensions protruding from either side of the rear sight forming a large ring which almost meets directly above the 'V' of the notch. The semi-buckhorn is similar but has a wider gently curving notch with the more precise 'V' at its center and is standard on classic Winchester and Marlin lever-action rifles. Express sights are most often used on heavy caliber rifles intended for the hunting of dangerous big game, and are in the form of a wide and large 'V' with a heavy white contrast line marking its bottom and a big white or gold bead front sight. In cases where the range is close and speed far outweighs accuracy (e.g. the shooter is being charged by a Cape Buffalo), the front sight is used like a shotgun bead; the rear sight is ignored, and the bead is placed on the target. When more time is available, the bead is placed in the 'V' of the rear sight.[2][edit] Advantages and disadvantagesOpen sights have many advantages: they are very common, inexpensive to produce, uncomplicated to use, sturdy, lightweight, resistant to severe environmental conditions, and they do not require batteries. On the other hand, they are not as precise as other forms of sights, and are difficult or impossible to adjust. Open sights also take much more time to usethe buckhorn type is the slowest, partridge, 'U' and 'V' type notch sights are only a bit quicker; only the express sight is relatively fast. In addition, open sights tend to block out the lower portion of the shooter's field of view by nature, and because of the depth of field limitations of the human eye, do not work as well for shooters with less than perfect vision.[2][edit] Aperture sights

Rear, rotating diopter drum sight of a SIG SG 550 assault rifle. The viewing aperture above the "3" (denoting the 300 m setting) can be seen.

Pictures taken under identical conditions through large (left) and small (right) diameter aperture sights, with camera focused on front sight.Aperture sights, also known as peep sights, range from the ghost ring sight, whose thin ring blurs to near invisibility (hence ghost), to target aperture sights that use large disks or other occluders with pinhole-sized apertures. In general, the thicker the ring, the more precise the sight, and the thinner the ring, the faster the sight.[2] The image to the right shows a shooter's eye view of the sight picture taken through large and small diameter apertures. The large diameter aperture provides a much brighter image of the target, and the ghosting of the rear ring is evident. The smaller aperture, while providing a much darker image of the target, provides a much greater depth of field (see pinhole camera for an explanation of this effect), yielding a much sharper image of the target.[2] The theory of operation behind the aperture sight is that the human eye will automatically center the front sight when looked through the rear aperture, thus ensuring accuracy.[2]These sights are used on target rifles of several disciplines and on several military rifles such as the M1 Garand, the No. 4 series Enfields and the M16 series of weapons along with several others. Peep sights are very effective in poor lighting, and have found favor with a few hunters who hunt in heavy cover.[citation needed][edit] Ghost ringsFor many shooters, the ghost ring sight is the fastest type of aperture sight. It is fairly accurate, easy to use, and obscures the target less than nearly all other non-optical sights. Because of this, ghost ring sights are commonly installed on combat shotguns and sub-machine guns (and to a much lesser extent, rifles). The ghost ring is a fairly recent innovation, and differs from traditional aperture sights in the extreme thinness of the rear ring, and the slightly thicker front sight. The thin ring minimizes the occlusion of the target, while the thicker front post makes it easy to find quickly.A ghost ring can also take form of a tube ranging from 36cm long, with the post mounted at the inside end of the tube. This type of ghost ring is used when there can be no front sight at the front end of the barrel. It is slightly slower to use, because the shooter's eye has to focus close on the post, then focus on the target. However, in situations when extremely fast sighting is required, the shooter can simply look through the tube, and it is simple to see if the view is straight down the tube.[edit] Target aperture sights

Rear aperture of a BRNO target sight. Note large disk and small aperture.

Front globe of a BRNO target sight. Note knurled nut holding in the replaceable front sight insert

A 10 metre air rifle target diopter and globe aperture sight pictureTarget aperture sights are designed for maximum precision. The rear sight element (often called diopter) is usually a large disk (up to 1inch or 2.5cm in diameter) with a small hole in the middle, and is placed close to the shooter's eye. High end target diopters normally accept accessories like adjustable diopter aperture and optical filter systems to ensure optimal sighting conditions for match shooters. Typical modern target shooting diopters offer windage and elevation corrections in 2mm (0.079in) to 4mm (0.157in) increments at 100m (109.4yd). Some ISSF (Olympic) shooting events require this precision level for sighting lines, since the score of the top competitors last 10 shots is expressed in 0.1s of scoring ring points.The complementing front sight element may be a simple bead or post, but is more often a globe type sight, which consists of a cylinder with a threaded cap, which allows differently shaped removable front sight elements to be used. Most common are posts of varying widths and heights or rings of varying diameterthese can be chosen by the shooter for the best fit to the target being used. Tinted transparent plastic insert elements may also be used, with a hole in the middle; these work the same way as an opaque ring, but provide a less obstructed view of the target. High end target front sight tunnels normally also accept accessories like adjustable aperture and optical systems to ensure optimal sighting conditions for match shooters. Some high end target sight line manufacturers also offer front sights with integrated aperture mechanisms.The use of round rear and front sighting elements for aiming at round targets, like used in ISSF match shooting, takes advantage of the natural ability of the eye and brain to easily align concentric circles (circles all having a common centre). Even for the maximum precision, there should still be a significant area of white visible around the bullseye and between the front and rear sight ring (if a front ring is being used). Since the best key to determining center is the amount of light passing through the apertures, a narrow, dim ring of light can actually be more difficult to work with than a larger, brighter ring. The precise sizes are quite subjective, and depend on both shooter preference and ambient lighting, which is why target rifles come with easily replaceable front sight inserts, and adjustable aperture mechanisms.Rifles from the late 19th century often featured one of two types of aperture sight called a tang sight or a ladder sight. Since the black powder used in muzzleloaders and early cartridges was not capable of propelling a bullet at high velocity, these sights had very large ranges of vertical adjustments, often on the order of several degrees, allowing very long shots to be made accurately. The .45-70 cartridge, for example, was tested by the military for accuracy at ranges of up to 1500 yards, which required 3 1/3 degrees of elevation. Both ladder and tang sights folded down when not in use to reduce the chance of damage to the sights. Ladder sights were mounted on the barrel, and could be used as sights in both the folded and unfolded states. Tang sights were mounted behind the action of the rifle, and provided a very long sight radius, and had to be unfolded for use, though rifles with tang sights often had open sights as well for close range use. Tang sights often had vernier scales, allowing adjustment down to a single minute of arc over the full range of the sight.Aperture sights on military rifles use a larger aperture with a thinner ring, and generally a simple post front sight. The extreme case of this is the ghost ring sight, a relatively recent innovation that may be the fastest type of iron sight to use, while still providing a degree of precision comparable to or better than most open sights. Ghost ring sights are commonly found on riot and combat shotguns and customized handguns, and they are also gaining ground as a backup sighting system on rifles.[edit] Shotgun beadsSince shotgun beads are only used by the peripheral vision, generally a larger, brighter bead works best. Fiber optic sights are becoming popular for shotguns, as they greatly increase the brightness of the bead by collecting light and directing it to the shooter's eye. Since the "rear sight" in the case of a shotgun is the shooter's eye position, adjusting the "sights" on a shotgun consists primarily of adjusting the stock to fit the shooter as well as possible.Bead sights are inferior in practical accuracy compared to rifle and ghost-ring sights, as they provide no rear sight to verify correct alignment with the front sight. While bead sights may be acceptable on sporting shotguns, they are best avoided for use on combat shotguns.The primary advantage of bead sights is that they do not interfere with the shooter's field of vision, allowing extremely rapid target acquisition, this is essential for fast moving targets such as clays and game. They are less expensive than rifle and ghost-ring sights.[edit] EnhancementsWhile iron sights are basically very simple, that simplicity also leads to a staggering variety of different implementations. In addition to the purely geometric considerations of the front blade and rear notch, there are some factors that need to be considered when choosing a set of iron sights for a particular purpose.[edit] Glare reductionGlare, particularly from the front sight, can be a significant problem with iron sights. The glare from the front sight can increase the apparent brightness of the light bar on one side of the sight, causing windage errors in aiming, or lower the apparent height of the front sight, causing elevation errors in aiming. Since the direction of the ambient light is rarely constant for a shooter, the resulting changing glare can significantly affect the point of aim.The most common solution to the problem of glare is a matte finish on the sights. Serrating or bead blasting the sight is a common solution for brightly finished sights, such as blued steel or stainless steel. Matte finishes such as parkerizing or matte black paint can also help. "Smoking" a sight by holding a match or cigarette lighter under the sight to deposit a fine layer of soot is a common technique used by many shooters, and in fact special soot producing cigarette type lighters are sold for use by competition shooters. Even a thin layer of mud or dirt applied to the sight will help kill the glare, as long as the coating is thin and consistent enough not to change the shape of the sights.Many target sights are designed with vertical or even undercut front sight blades, which reduces the angles at which light will produce glare off the sightthe downside of these sights is that they tend to snag on clothing, branches, and other materials, so they are only common on target guns. Sight hoods reduce the chances of snagging an undercut sight and are common on some types of rifles, particularly lever action rifles, but they are prohibited in some shooting disciplines such as some classes of handgun metallic silhouette shooting.[edit] Fixed vs. adjustable sightsThe downside to adjustable sights is the inherent fragility of the moving parts. A fixed sight is a solid piece of metal, usually steel, and if firmly attached to the gun, little is going to be able to damage it beyond usefulness. Adjustable sights, on the other hand, are bulkier, and have parts that must move relative to the gun. Solid impact on an adjustable sight will usually knock it out of adjustment, if not knock it right off the gun. Because of this, guns for self defense or military use either have fixed sights, or sights with "wings" on the sides for protection (such as those on the M4 carbine).Iron sights used for hunting guns tend to be a compromise. They will be adjustable, but only with toolsgenerally either a small screwdriver or an allen wrench. They will be compact and heavily built, and designed to lock securely into position. Target sights, on the other hand, are much bulkier and easier to adjust. They generally have large knobs to control horizontal and vertical movement without tools, and often they are designed to be quickly and easily detachable from the gun so they can be stored separately in their own protective case.[edit] Contrast enhancements

Various methods of open sight contrast enhancement. Left to right: Three dot, white outline, Straight-eight, red insert, dot and bar, gold bead.

Self-luminous tritium-illuminated night sights of a SIG SG 550 assault rifle.

Tritium-illuminated handgun night sights.

Green fibre optic contrast enhancement rods used in an adjustable open sight rear element.While target shooters generally prefer a matte black finish to their sights, to reduce the chance of glare and increase the contrast between the sights and the light bars, black sights don't offer good visibility with dark targets or in low light conditions, such as those often encountered in hunting, military, or self defense situations. A variety of different contrast enhancements to the basic Patridge type sight and others have been developed to address this deficiency. It should be noted that the contrast enhancement of the front sight has to be somewhat larger compared to the contrast enhancement(s) used for the rear sight if all contrast enhancements should appear about equally large from the shooters perspective.Three-dot: On semi-automatic handguns, the most common type of enhancement is a bright white dot painted on the front sight near the top of the blade, and a dot on each side of the rear sight notch. In low lighting conditions the front sight dot is centered horizontally between the rear sight dots, with the target placed above the middle (front) dot. Some sight vendors offer differently colored dots for the front and rear sights.[4]White outline rear: A contrast variation which uses a dot front sight with a thick and bright white outline around the rear sight notch.[5]Straight Eight: Heinie Specialty Products produces a variant of high visibility sights in which a single dot front sight and a rear notch with a dot below can be lined up vertically to form a figure "eight".[6]Sight inserts: Popular on revolvers, this enhancement consists of a colored plastic insert in the front sight blade, usually red or orange in color.[7]Bar/Dot or Express sight: Similar to the Straight Eight type, this type of sight is traditional on express rifles and is also found on some handguns. The open, V-shaped rear allows for faster acquisition and wider field of view, though less accurate for longer range precision type shooting. The dot on the front sight is aligned or set directly above the vertical bar on the rear sight, commonly referred to as "dotting the 'I'".[4]Gold bead: Preferred by many competitors in IPSC and IDPA shooting.[4]Night sights: On Tactical firearms, the contrast enhancements can consist of trasers containing tritium gas, which emit a dim light due to the radioactive decay of the tritium, and fluorescent material. Self-luminous tritium sights provide vital visibility in extremely low light situations where normal sights would be degraded or even useless.[8]Fiber optic: A growing trend, started on air rifles and muzzleloaders, is the use of short pieces of optical fiber for the dots, made in such a way that ambient light falling on the length of the fiber is concentrated at the tip, making the dots slightly brighter than the surroundings.This method is most commonly used in front sights, but many makers offer sights that use fiber optics on front and rear sights. Fiber optic sights can now be found on handguns, rifles, and shotguns, both as aftermarket accessories and a growing number of factory guns.[9]

[edit] Concealed carrySpecific to handguns is the issue of concealed carry. While police and military personnel generally carry their handguns in open holsters that provide easy and unobstructed access, civilians in areas where concealed carry is allowed, and who choose to carry concealed, are usually required to carry their firearms concealed under clothing or some other form of cover, such as a fanny pack or purse. The high contrast, sharp edges that are popular with target shooters can be dangerous on a concealed firearmnot only can they tear skin and clothing when drawn, but if they become tangled during the draw, entanglement can have lethal consequences for the shooter.The challenge for a designer of sights for a concealable handgun is to pick the right compromise between high visibility and minimum hindrance. Rather than the vertical or even undercut front sights found on target handguns, the front sights of a concealed carry gun will be sloped. The rear sight will not be a vertical plate, but will have depth to provide a gentle slope, and the sight will fit the gun more closely, with no gaps or overlaps to snag, or to collect dirt and sweat which can cause corrosion.Design criteria for sights for use on a concealed handgun also have to consider the potential conditions in which they will be usedprobably low light, close range, and with the operator under significant stress due to an imminent threat. Some unusual solutions have been devised, such as the trapezoidal sights used by Steyr (shown as G in Types of Iron Sights), or the "gutter sight" used by the highly modified ASP S&W model 39.[edit] Optical sightsFor precision applications such as hunting or sniping the iron sights are usually replaced by a telescopic sight, and for target shooting and combat operations low-power magnified or unmagnified optical sights such as reflector (reflex) sights are increasingly common. Iron Sights may still be fitted alongside a telescopic sight and are referred to as Back Up Iron Sights (Acronym B.U.I.S), typically BUIS sights fold down when not in use.[edit] Adjusting for accuracy

This section contains instructions, advice, or how-to content. The purpose of Wikipedia is to present facts, not to train. Please help improve this article either by rewriting the how-to content or by moving it to Wikiversity or Wikibooks. (November 2009)

This section may contain original research. Please improve it by verifying the claims made and adding references. Statements consisting only of original research may be removed. More details may be available on the talk page. (November 2009)If the sights are not aligned correctly, then the sights should be adjusted to bring the line of sight to meet the point of impact. Theoretically, this can be done with a single shotclamp the firearm into a vise, fire one shot, then adjust the sights so they are pointing at the hole in the target. In reality, it generally takes a number of shots to establish a group, then the sights are adjusted to move the line of sight closer to the group, and the process is repeated iteratively until the sights are correctly aligned.The general rule is the rear sight is moved in the SAME direction you wish to move the point of impact. For example, if the point of impact is LEFT and BELOW the target, and you wish to move the point of impact to the center, then move the rear sight RIGHT and UP. The front sight moves the opposite direction, so it would move LEFT and DOWN.Detailed instructions for adjusting the sights:To move the line of sight DOWN (the shot hit BELOW the point of aim) the REAR sight is RAISED or the FRONT sight is LOWERED.To move the line of sight UP (the shot hit ABOVE the point of aim) the REAR sight is LOWERED or the FRONT sight is RAISED. (Example below)To move the line of sight LEFT (the shot hit LEFT of the point of aim) the REAR sight is moved RIGHT, or the FRONT sight is moved LEFT.To move the line of sight RIGHT (the shot hit RIGHT of the point of aim) the REAR sight is moved LEFT, or the FRONT sight is moved RIGHT.

Many target sights have click adjustments, where a detent in the adjustment screws allows the sight to move the line of sight a certain angular distance with each click. This distance is usually specified in minutes of arc, which translate to approximately 1inch at 100 yards. On a firearm with 1 minute clicks, then, it would take 1 click to move 1inch at 100 yards, 2 clicks to move 1inch at 50 yards, 4 clicks to move 1inch at 25 yards. If click adjustments are not available, or the click interval is not known, then the distance to lengthen or shorten the sight for a given point of aim adjustment is:D1 / R1 = D2 / R2For rear sight adjustments:D1 is the distance between point of aim and point of impact.R1 is range from front sight to target.D2 is the length the rear sight must change by.R2 is the distance between front and rear sights.

For front sight adjustments:D1 is the distance between point of aim and point of impact.R1 is range from rear sight to target.D2 is the length the front sight must change by.R2 is the sight radius distance between front and rear sights.

This formula calculates the MAGNITUDE ONLY of the sight height change; refer to the instructions above to find the correct direction for the adjustment (front or rear sight, longer or shorter). Likewise, all distances must be in the same units. That is, if a change in inches to the sight height is desired, and one is shooting on a 100-yard range, then R1 (100 yd) must be converted to inches (100 36 = 3600inches) before using this distance in the equation.An example: Consider a rifle with a distance between front and rear sights of 26.25 inches, firing on a 50-yard (1800in) range, with point of impact 5.3 inches too high on the target, having a front sight blade that is 0.505 inches high mounted in a dovetail. How much must the front sight blade height be changed by to fix this problem? (It will be assumed that the muzzle of the rifle intrudes into the range space for following typical gun range safety protocols, and the rear sight is hence 50 yards from the target.)D2 = R2(D1/R1) = 26.25(5.3/1800) = 0.077" (magnitude of change to front sight height)Since the gun is hitting too high, the front sight must be lengthened by this much per the instructions cited previously; hence, the front sight must be replaced with a blade that is 0.505" + 0.077" = 0.582" high. With this correction, the rifle will hit the desired point of impact, all other factors being equal.

Telescopic sightFrom Wikipedia, the free encyclopediaJump to: navigation, search "Scope" redirects here. For other uses, see Scope (disambiguation).

View through a 4x rifle scope.A telescopic sight, commonly called a scope, is a sighting device that is based on an optical refracting telescope. They are equipped with some form of graphic image pattern (a reticle) mounted in an optically appropriate position in the their optical system to give an accurate aiming point. Telescopic sights are used with all types of systems that require accurate aiming but are most commonly found on guns. Other types of sights are iron sights, reflector (reflex) sights, and laser sights.Contents[hide]1 History2 Types 2.1 Optical parameters3 Reticles 3.1 Mil-dot reticles3.2 Reticle focal plane3.3 Reticle illumination4 Parallax compensation5 Bullet Drop Compensation6 Adjustment controls7 Accessories8 Optronic technologies 8.1 Integrated laser rangefinder8.2 Ballistic support devices8.3 CCD and LCD technology9 Mounting 9.1 Scope bases9.2 Scope rings9.3 Scope mounting rails9.4 Rail interface systems9.5 Mounting issues10 Uses 10.1 Military11 See also12 References13 External links

[edit] History

This section requires expansion.The first experiments directed to give shooters optical aiming aids go back to the early 17th century. For centuries different optical aiming aids and primitive predecessors of telescopic sights were created that had practical or performance limitations.The first documented telescopic rifle sight was invented between 1835 and 1840. In a book titled The Improved American Rifle, written in 1844, John R. Chapman documents the first telescopic sights made by Morgan James of Utica, NY. Chapman, the author, being a civil engineer, gave James the concepts and some of the design, whereupon they produced the Chapman-James sight. In 1855, William Malcolm of Syracuse, NY began producing his own sight. Malcolm used an original design incorporating achromatic lenses like those used in telescopes, and improved the windage and elevation adjustments. They were between 3X and 20X or greater. Malcolm's and those made by Mr. L.M. Amidon of Vermont were the standard during the Civil War.[1][2]Still other telescopic rifle sights of the same period were the Davidson telescopic sight and the Parker Hale telescopic sight.[3][4]An early practical refractor telescope based telescopic sight was built in 1880 by August Fiedler (Stronsdorf, Austria), forestry commissioner of Prince Reuss.[5][6] Later telescopic sights with extra long eye relief became available for handgun and scout rifle use. A historic example of a telescopic sight with a long eye relief is the German ZF41 which was used during World War II on Karabiner 98k rifles.An early example of a man portable telescopic sight for low visibility/night use is the Zielgert (aiming device) 1229 (ZG 1229), also known by its code name Vampir. The ZG 1229 Vampir was a Generation 0 active infrared night vision device developed for the Wehrmacht for the StG 44 assault rifle, intended primarily for night use. The issuing of the ZG 1229 Vampir system to the military started in 1944 and it was used on a small scale in combat from February 1945 until the final stages of World War II.[edit] Types

A Swift model 687M variable power rifle scope with parallax compensation (the ring around the objective lens is used for making parallax adjustments).Telescopic sights are classified in terms of the optical magnification and the objective lens diameter, e.g. 1050. This would denote 10 times magnification with a 50mm objective lens. In general terms, larger objective lens diameters, due to their ability to gather larger amounts of light, provide a larger exit pupil and hence provide a brighter image at the eyepiece. On fixed magnification sights the magnification power and objective diameter should be chosen on the basis of the intended use.There are also telescopic sights with variable magnification. The magnification can be varied by manually operating a zoom mechanism. Variable sights offer more flexibility regarding shooting at varying ranges, targets and light conditions and offer a relative wide field of view at lower magnification settings. The syntax for variable sights is the following: minimal magnification maximum magnification objective lens, for example, 3940.Confusingly, some older telescopic sights, mainly of German or other European manufacture, have a different classification where the second part of the designation refers to 'light gathering power.' In these cases, a 481 (4 magnification) sight would be presumed to have a brighter sight picture than a 2.570 (2.5 magnification), but the objective lens diameter would not bear any direct relation to picture brightness, as brightness is affected also by the magnification factor. Typically objective lenses on early sights are smaller than modern sights, in these examples the 481 would have an objective approximately 32mm diameter and the 2.570 might be approximately 25mm.[edit] Optical parametersTelescopic sights are usually designed for the specific application for which they are intended. Those different designs create certain optical parameters. Those parameters are:Magnification The ratio of the focal length of the eyepiece divided into the focal length of the objective gives the linear magnifying power of telescopes. A magnification of factor 10, for example, produces an image as if one were 10 times closer to the object. The amount of magnification depends upon the application the telescopic sight is designed for. Lower magnifications lead to less susceptibility to shaking. A larger magnification leads to a smaller field of view.Objective lens diameter The diameter of the objective lens determines how much light can be gathered to form an image. It is usually expressed in millimeters.Field of view The field of view of a telescopic sight is determined by its optical design. It is usually notated in a linear value, such as how many meters (feet) in width will be seen at 100 m (100 yd), or in an angular value of how many degrees can be viewed.Exit pupil Telescopic sights concentrate the light gathered by the objective into a beam, the exit pupil, whose diameter is the objective diameter divided by the magnifying power. For maximum effective light-gathering and brightest image, the exit pupil should equal the diameter of the fully dilated iris of the human eye about 7mm, reducing with age. If the cone of light streaming out of the eyepiece is larger than the pupil it is going into, any light larger than the pupil is wasted in terms of providing information to the eye.However, a larger exit pupil makes it easier to put the eye where it can receive the light: anywhere in the large exit pupil cone of light will do. This ease of placement helps avoid vignetting, which is a darkened or obscured view that occurs when the light path is partially blocked. And, it means that the image can be quickly found which is important when aiming at game animals that move rapidly. A narrow exit pupil telescopic sight may also be fatiguing because the instrument must be held exactly in place in front of the eyes to provide a useful image. Finally, many people in Europe use their telescopic sights at dusk, dawn and at night, when their pupils are larger. Thus the daytime exit pupil of about 3 to 4mm is not a universally desirable standard. For comfort, ease of use, and flexibility in applications, larger telescopic sights with larger exit pupils are satisfying choices even if their capability is not fully used by day.Eye relief Eye relief is the distance from the rear eyepiece lens to the exit pupil or eye point.[7] It is the distance the observer must position his or her eye behind the eyepiece in order to see an unvignetted image. The longer the focal length of the eyepiece, the greater the eye relief. Typical telescopic sights may have eye relief ranging from 25mm (1in) to over 100mm (4in), but telescopic sights intended for scout rifles or handguns need much longer eye relief to present an unvignetted image. Telescopic sights with relatively long eye relief are favourable to avoid recoil induced facial and eye injuries and use in instances where it is difficult to hold the eyepiece steady. Eye relief can be particularly important for eyeglass wearers. The eye of an eyeglass wearer is typically further from the eye piece which necessitates a longer eye relief in order to still see the entire field of view.[edit] Reticles

Various reticles.

Rangefinder reticle.Telescopic sights come with a variety of different reticles, ranging from the traditional crosshairs to complex reticles designed to allow the shooter to estimate accurately the range to a target, to compensate for the bullet drop, and to compensate for the windage required due to crosswinds. A user can estimate the range to objects of known size, the size of objects at known distances, and even roughly compensate for both bullet drop and wind drifts at known ranges with a reticle-equipped scope.For example, with a typical Leupold brand duplex 16 Minute of Angle (MOA) reticle (of a type as shown in image B) on a fixed power scope, the distance from post to post (that is, between the heavy lines of the reticle spanning the center of the scope picture) is approximately 32inches (81.3cm) at 200 yards (183 m), or, equivalently, approximately 16inches (40.65cm) from the center to any post at 200 yards. If a target of a known diameter of 16inches fills just half of the total post-to-post distance (i.e. filling from scope center to post), then the distance to target is approximately 200 yards (183 m). With a target of a diameter of 16inches that fills the entire sight picture from post to post, the range is approximately 100 yards. Other ranges can be similarly estimated accurately in an analog fashion for known target sizes through proportionality calculations. Holdover, for estimating vertical point of aim offset required for bullet drop compensation on level terrain, and horizontal windage offset (for estimating side to side point of aim offsets required for wind effect corrections) can similarly be compensated for through using approximations based on the wind speed (from observing flags or other objects) by a trained user through using the reticle marks. The less-commonly used holdunder, used for shooting on sloping terrain, can even be estimated by an appropriately-skilled user with a reticle-equipped scope, once the slope of the terrain and the slant range to target are both known.There are two main types of reticles:Wire reticlesEtched reticles

Wire reticles are the oldest type of reticles and are made out of metal wire. They are mounted in an optically appropriate position in the telescopic sight's tube. Etched reticles are images of the desired reticle layout that are etched on an optic element. This optical element (lens) with the etched reticle is then mounted in the telescopic sights tube as an integrated part of the optics chain of the sight. When backlit through the ocular a wire reticle will reflect incoming light and not present a fully opaque (black) reticule with high-contrast. An etched reticle will stay fully opaque (black) if backlit. Etched reticles are by most considered to be a more refined solution and offer greater reticle lay out flexibility. Because of this some manufacturers can provide client designed custom reticles on special order. In the more expensive and high end contemporary telescopic sights etched reticles dominate the market. In cheaper telescopic sights wire reticles are still often mounted to avoid a rather specialized and costly production step.[edit] Mil-dot reticles

Dutch Schmidt & Bender mil-dot reticle.

If the helmeted head of a man ( 0.25 m tall) fits between the fourth bar and the horizontal line, the man is at approximately 100 meters distance. When the upper part of the body of a man ( 1 m tall) fits under the first line, he stands at approximately 400 meters distance.Modern military and law enforcement reticles are generally designed for (stadiametric) rangefinding purposes. Perhaps the most flexible ranging reticle is the "Mil-dot" reticle, which consists of duplex crosshairs with small dots at milliradian (Mil) intervals in the field of view. A milliradian equates to 3.43774677078493 MOA, that is, approximately 21.6inches at 600 yards; each MOA equates to 1.0471975511966inch at 100 yards, often rounded to 1inch at 100 yards for fast mental calculations.Users who use the metric system are better off with a Mil-dot reticle, since they do not have to hassle with the unnecessary complications of a non metric system of measurement during mental calculations. Also the Mil-dot measurements and ranging calculations are always exact in the metric system.A trained user can relatively accurately measure the range to objects of known size, the size of objects at known distances, and compensate for both bullet drop and wind drifts at known ranges with a Mil-dot reticle-equipped scope.This is what a Netherlands Army sniper sees through his Schmidt & Bender 3-12x50 PM II[8] telescopic sight. The Mil-dots can be seen on the cross hairs. By means of a mathematical formula - (width or height of the target/ number of mil of dots) x 1000 = distance - the user can measure the range to a target. An object of 1 meter tall or wide is exactly 1 Mil tall or wide at 1000 meters distance. If the user sees an object of 1.8 m tall for example as three mil dots tall through the riflescope the object is at 600 m distance - (1.8 / 3) x 1000 = 600.The four horizontal bars over the horizontal line are also intended for (quick) ranging purposes.(Edit The mil dot was designed around the Milliradian... 36in at 1000 yards. Meters can be supplemented. The mil dot is utilized with three variables, two of which have to be known in order to effectively use. http://mil-dot.com Edit)[edit] Reticle focal plane

Typical internal construction of a scope with its reticle in the First Focal Plane.The reticle may be located at the front or rear focal plane (First Focal Plane (FFP) or Second Focal Plane (SFP)) of the telescopic sight. On fixed power telescopic sights there is no significant difference, but on variable power telescopic sights the front plane reticle remains at a constant size compared to the target, while rear plane reticles remain a constant size to the user as the target image grows and shrinks. Front focal plane reticles are slightly more durable, but most American users prefer that the reticle remains constant as the image changes size, so nearly all modern American variable power telescopic sights are rear focal plane designs. European high end optics manufacturers often leave the customer the choice between a FFP or SFP mounted reticle.Variable power telescopic sights with front focal plane reticles have no problems with point of impact shifts. Variable power telescopic sights with rear focal plane reticles can have slight point of impact shifts through their magnification range caused by the positioning of the reticle in the mechanical zoom mechanism in the rear part of the telescopic sight. Normally these impact shifts are insignificant but make accuracy oriented users, that wish to use their telescopic sight trouble-free at several magnification levels, often opt for front focal plane reticles. Around the year 2005 Zeiss[9] was the first high end European telescopic sight manufacturer who brought out variable magnification military grade telescopic sight models with rear focal plane mounted reticles. They get around impermissible impact shifts for these sights by laboriously hand adjusting every military grade telescopic sight. The American high end telescopic sight manufacturer U.S. Optics Inc.[10] also offers variable magnification military grade telescopic sight models with rear focal plane mounted reticles.[edit] Reticle illuminationEither type of reticle can be illuminated for use in low-light or daytime conditions. With any illuminated low-light reticle, it is essential that its brightness can be adjusted. A reticle that is too bright will cause glare in the operators eye, interfering with his ability to see in low-light conditions. This is because the pupil of the human eye closes quickly upon receiving any source of light. Most illuminated reticles provide adjustable brightness settings to adjust the reticle precisely to the ambient light.Illumination is usually provided by a battery powered LED, though other electric light sources can be used. The light is projected forward through the scope, and reflects off the back surface of the reticle. Red is the most common colour used, as it least impedes the shooter's night vision. This illumination method can be used to provide both daytime and low-light conditions reticle illumination.Radioactive isotopes can also be used as a light source, to provide an illuminated reticule for low-light condition aiming. In sights like the SUSAT or Elcan C79 Optical Sight tritium-illuminated reticles are used for low-light condition aiming. Trijicon Corporation uses tritium in their combat and hunting-grade firearm optics, including the ACOG. The (radioactive) tritium light source has to be replaced every 812 years, since it gradually loses its brightness due to radioactive decay.With fiber optics ambient (day)light can be collected and directed to an illuminated daytime reticle. Fiber optics reticles automatically interact with the ambient light level that dictates the brightness of the reticle. Trijicon uses fiber optics combined with other low-light conditions illumination methods in their AccuPoint telescopic sights and some of their ACOG sights models.[edit] Parallax compensationParallax problems result from the image from the objective not being coincident with the reticle. If the image is not coplanar with the reticle (that is the image of the objective is either in front of or behind the reticle), then putting your eye at different points behind the ocular causes the reticle crosshairs to appear to be at different points on the target. This optical effect causes parallax induced aiming errors that can make a telescopic sight user miss a small target at a distance for which the telescopic sight was not parallax adjusted.To eliminate parallax induced aiming errors, telescopic sights can be equipped with a parallax compensation mechanism which basically consists of a movable optical element that enables the optical system to project the picture of objects at varying distances and the reticle crosshairs pictures together in exactly the same optical plane. There are two main methods to achieve this.By making the objective lens of the telescopic sight adjustable so the telescopic sight can compensate parallax errors. These models are often called AO or A/O models, for adjustable objective.By making an internal lens in the internal optical groups mounted somewhere in front of the reticle plane adjustable so the telescopic sight can compensate parallax errors. This method is technically more complicated to build, but generally more liked by parallax adjustable telescopic sight usersunlike AO models, which are read from the top, the sidewheel's setting can be read with minimal movement of the head. These models are often called side focus or sidewheel models.[11]

Most telescopic sights lack parallax compensation because they can perform very acceptably without this refinement. Telescopic sights manufacturers adjust these scopes at a distance that best suits their intended usage. Typical standard factory parallax adjustment distances for hunting telescopic sights are 100yd or 100m to make them suited for hunting shots that rarely exceed 300yd/m. Some target and military style telescopic sights without parallax compensation may be adjusted to be parallax free at ranges up to 300yd/m to make them better suited for aiming at longer ranges.[12] Scopes for rimfires, shotguns, and muzzleloaders will have shorter parallax settings, commonly 50yd/m[13] for rimfire scopes and 100yd/m[14] for shotguns and muzzleloaders. Scopes for airguns are very often found with adjustable parallax, usually in the form of an adjustable objective, or AO. These may adjust down as far as 3yards (2.74m).[15]The reason why scopes intended for short range use are often equipped with parallax compensation is that at short range (and at high magnification) parallax errors become more noticeable. A typical scope objective has a focal length of 100mm. An optical ideal 10 scope in this example has been perfectly parallax corrected at 1000m and functions flawlessly at that distance. If the same scope is used at 100m the target-picture would be projected (1000m / 100m) / 100mm = 0.1mm behind the reticle plane. At 10 magnification the error would be 10 0.1mm = 1mm at the ocular. If the same scope was used at 10m the target-picture would be (1000m /10m) / 100mm = 1mm projected behind the reticle plane. When magnified ten times the error would be 10mm at the ocular.[edit] Bullet Drop CompensationBullet Drop Compensation (BDC) (sometimes referred to as ballistic elevation) is a feature available on some rifle scopes. The feature compensates for the effect of gravity on the bullet at given distances (referred to as "bullet drop"). The feature must be tuned for the particular ballistic trajectory of a particular combination of rifle and cartridge at a predefined air density. Inevitable BDC induced errors will occur if the environmental and meteorological circumstances deviate from the circumstances the BDC was calibrated for. Marksmen can be trained to compensate for these errors.[edit] Adjustment controls

The adjustment controls of a telescopic sight with an elevation adjustment knob featuring a zero-stop and second revolution indicator.A telescopic sight can have several adjustment controls.Focusing control at the ocular end of the sight - meant to obtain a sharp picture of the object and reticle.Elevation or vertical adjustment control of the reticle. Zero-stop elevation controls can be set to prevent inadvertently dialing the adjustment knob "below" the primary zero (usually 100 meters or 100 yards for long-range scopes), or at least prevent dialing more than a couple adjustment clicks below zero. This feature is also useful on long-range scopes because it allows the shooter to physically verify the elevation knob is dialed all the way down avoiding confusion regarding the elevation status on two- or multi-revolution elevation knobs.Windage or horizontal adjustment control of the reticle.Magnification control - meant to change the magnification by turning a ring that is generally marked with several magnification power levels.Illumination adjustment control of the reticule - meant to regulate the brightness level of the lit parts of the reticles crosshairs.Parallax compensation control.

Most contemporary telescopic sights offer the first three adjustment controls. The other three are found on telescopic sights that offer a variable magnification, an illuminated reticle and/or parallax compensation. A rather common problem with the elevation and windage adjustment controls is that once smooth working adjustment turrets get stuck over the years. This is generally caused by long time lack of movement in the lubricated turret mechanisms.Older telescopic sights often did not offer windage and elevation adjustments in the scope, but rather used adjustable mounts to provide adjustment. Some modern mounts also allow for adjustment, but it is generally intended to supplement the scope adjustments. For example, some situations require fairly extreme elevation adjustments, such as very short range shooting common with airguns, or very long range shooting, where the bullet drop becomes very significant. In this case, rather than adjusting the scope to the extremes of its elevation adjustment, the scope mount can be adjusted. This allows the scope to operate near the center of its adjustment range. Some companies offer adjustable bases, while others offer bases with a given amount of elevation built in. The adjustable bases are more flexible, but the fixed bases are more durable, as adjustable bases may loosen and shift under recoil.[16][17][edit] Accessories

Scrome LTE J10 F1 with a lens hood mounted at the ocular and a flip-open cover at the objective mounted on a PGM Hecate II.Typical accessories for telescopic sights are:Lens hoods for mounting on the objective and/or ocular to reduce/eliminate image quality impairing stray light.Lens hoods that extend the full length of a gun barrel to improve image quality by blocking out shot strings induced mirage ("heat waves" or aberrations resulting from a hot gun barrel).Covers to protect the objective and/or ocular external lens surface against foul weather and damage. There are slide-over, bikini and flip-open type covers without or with transparent covering material.Optical filters like Grey, Yellow and Polarising filters to optimize image quality in various lighting conditions.Kill Flash or honeycomb filters to eliminate light reflections from the objective that could compromise a sniper.Eye-safe laser filters to protect operators against being wounded/blinded by laser light sources. These filters are often an internal part in the assembly of lens elements.Transit and protection pouches and cases.

[edit] Optronic technologies[edit] Integrated laser rangefinderIn 1997 Swarovski Optik introduced the LRS series telescopic sight, the first riflescope on the civilian market with an integrated laser rangefinder.[18] The LRS 2-12x50 sight can measure ranges up to 600 m (660 yd).[19] The LRS sights are currently (2008) not produced anymore, but sights with similar features are commercially available from several manufacturers.[edit] Ballistic support devicesAn integrated ballistic computer/riflescope system known as BORS has been developed by the Barrett Firearms Company and became commercially available around 2007. The BORS module is in essence an electronic Bullet Drop Compensation (BDC) sensor/calculator package intended for long-range sniping out to 2500 m (2734 yd) for some telescopic sight models made by Leupold and Nightforce. To establish the appropriate elevation setting the shooter needs to enter the ammunition type into the BORS (using touch pads on the BORS console) determine the range (either mechanically or through a laser rangefinder) and crank the elevation knob on the scope until the proper range appears in the BORS display. The BORS automatically determines the air density, as well as the cant or tilt in the rifle itself, and incorporates these environmental factors into its elevation calculations.[20]The SAM (Shooter-supporting Attachment Module) measures and provides aiming and ballistic relevant data and displays this to the user in the ocular of the Zeiss 6-24x72 telescopic sight it is developed for.[21] The SAM has different sensors integrated (temperature, air pressure, shooting angle) and calculates the actual ballistic compensation. All indications are displayed in the ocular. It memorizes up to 4 different ballistics and 4 different firing tables. So it is possible to use 1 SAM with 4 total different weapons without an additional adjustment.[edit] CCD and LCD technologyA totally different approach has been applied in the ELCAN DigitalHunter Digital Rifle Scope series which combines CCD and LCD technology with electronic ballistics compensation, automatic video capture, 4 field selectable reticles and customizable reticles. In 2008 a DigitalHunter DayNight Riflescope that uses infrared light captured by the CCD to enhance low light capabilities became available. It is also possible to attach infrared light sources to use this telescopic sight as an active night sight in total darkness. Some jurisdictions however forbid or limit to use of night vision devices for civilian or gun aiming use.[22][edit] Mounting

Colt Python Silhouette, with 8-inch barrel, factory scope, and case 500 made in 1981 by the Colt Custom Gun Shop.As very few firearms come with built-in telescopic sights (military designs such as the Steyr AUG, SAR 21 and the H&K G36 being exceptions) mounting a scope to a firearm requires additional equipment. Equipment is available to mount scopes on most production firearms. A typical scope mounting system consists of two parts, the scope base and the scope rings. By picking the appropriate combination of scope base to fit the firearm and scope rings to fit the scope, a wide range of scopes may be mounted to most firearms. With the appropriate combination of adjustable scope bases and scope rings it is also possible to mount several telescopic sights on the same gun to make the gun more versatile. However, it is important to take into consideration whether or not a gun is particularly hard to mount. If it is or if a gun is intended for long-range shooting, it could be that the amount of vertical adjustment range is smaller than required. This can be solved with the help of a vertically canted base or canted rings. Typical cant angles offered by mounting components manufacturers are 20 and 30 MOA. It is always wise to buy telescopic sights that provide a decent adjustment range, preferably at least 60 MOA or more.[23][edit] Scope basesThe base is attached to the rifle, usually with screws, and is often designed to have a low profile, and to allow use of the iron sights if the scope is not present. Some manufacturers provide integral bases on many of their firearms; an example of such a firearm is the Ruger Super Redhawk revolver. The most commonly encountered mounting systems are the 3/8inch (9.5mm) and the 11mm dovetail mounts (sometimes called tip-off mounts), commonly found on rimfires and air guns, the Weaver type base and the STANAG 2324 (MIL-STD-1913 "Picatinny rail") base. Ruger uses a proprietary scope base system, though adapters are available to convert the Ruger bases into Weaver type bases. Scope base and mounting systems are also manufactured in Europe. Specialized manufacturers like Ernst Apel GmbH[24][25] offer an elaborate program of mounting solutions for many different guns. Some of the European mounting solutions are virtually unknown and hence rarely applied in America. Many European gun manufacturers also developed and offer proprietary scope base systems for their guns, for example Sako has tapered dovetails and Tikka uses 16mm dovetail.[edit] Scope ringsIn addition to needing the right type of connector to attach to the desired base, scope rings must be used to hold the scope to the mount. The rings must be of the proper size to fit the scope; common sizes are 3/4inch (19.05mm), 22mm, 1inch (25.4mm), 26mm, 30mm and 34mm. Red dot sights commonly are found in larger sizes, such as 40mm, and these often use ringless mounting systems designed to fit dovetail or Weaver type bases. Rings are also available in a variety of heights and materials. Ring height is chosen to place the scope high enough to clear the firearm, and at a height comfortable for the shooter.[edit] Scope mounting rails

Schmidt & Bender Classic 4x36 with mounting rails fitted with a Suhler claw mount on a Gebrder Merkel Drilling. Manufactured in May, 1985.European telescopic sight manufacturers often offer the option to have mounting rails underneath the riflescope to provide for mounting solutions that do not use scope rings or a single scope ring around the objective of the scope. These rails are an integral part of the scope body and can not be removed. The mounting rail permits the riflescope to be securely and tension-free mounted at the preferred height and correct distance from the shooter's eye and on different guns.There are several mounting rail systems offered:Standard prismZeiss ZM/VM, also used by DOCTERSwarovski Optik SRSchmidt & Bender Convex

The traditional standard prism mounting rail system requires to have the scope rail drilled from the side for fixture screws. The more recent propriety systems mainly offer aesthetic advantages for people who have problems with redundant drill holes in sight in case the riflescope is used on different guns. To avoid drilling the scope rail, the propriety rail mounting systems have special shape connections machined in the inside of the rail. These shape connections prevent ever showing any exterior damage from mounting work on the rifle scope. The propriety rail systems use matching slide-in mount fasteners to connect the riflescope to the gun. Some propriety rails also offer the possibility to tilt the scope up to 1 to the left or right.[edit] Rail interface systems

Telescopic sight fitted with scope rings on a Picatinny/MIL-STD-1913 rail mounted above the receiver of a sniper rifle.For mounting telescopic sights and/or other accessories to guns several rail interface systems are available to provide a standardized mounting platform. Probably the best known rail interface system is the Picatinny rail or STANAG 2324 rail or MIL-STD-1913 rail used by NATO forces and other official and civil users. The name of this interface system comes from the Picatinny Arsenal in New Jersey, where it was originally tested and was used to distinguish it from other rail standards at the time. The Picatinny rail comprises a series of ridges with a T-shaped cross-section interspersed with flat "spacing slots". Telescopic sight mounting rings are mounted either by sliding them on from one end or the other; by means of a "rail-grabber" which is clamped to the rail with bolts, thumbscrews or levers; or onto the slots between the raised sections. Another commercially available rail interface system is the Weaver rail mount from Weaver Optics. The only difference between the Picatinny rail and the Weaver rail is the size of the slots, although many rail-grabber-mounted accessories can be used on either type of rail.[edit] Mounting issuesScopes for use on light recoiling firearms, such as rimfire guns, can be mounted with a single ring, and this method is not uncommon on handguns, where space is at a premium. Most scopes are mounted with two rings, one in the front half of the scope and one on the back half, which provides additional strength and support. The heaviest recoiling firearms, such as Thompson Center Arms Contender pistols in heavy recoiling calibers, will use three rings for maximum support of the scope. Use of too few rings can result not only in the scope moving under recoil, but also excessive torque on the scope tube as the gun rolls up under recoil.Scopes on heavy recoiling firearms and spring piston airguns (which have a heavy "reverse recoil" caused by the piston reaching the end of its travel) suffer from a condition called scope creep, where the inertia of the scope holds it still as the firearm recoils under it. Because of this, scope rings must be precisely fitted to the scope, and tightened very consistently to provide maximum hold without putting uneven stress on the body of the scope. Rings that are out of round, misaligned in the bases, or tightened unevenly can warp or crush the body of the scope.[26]Another problem is mounting a scope on a rifle, such as some lever action designs, where the shell is ejected out the top of the rifle. Usually this results in the scope being offset to one side (to the left for right-handed people, right for left-handed) to allow the shell to clear the scope. Alternately a scout rifle type mount can be used, which places a long eye relief scope forward of the action.A firearm may not always be able to fit all aiming optics solutions, so it is wise to have a preferred aiming optics solution first reviewed by a professional.[edit] UsesTelescopic sights have both advantages and disadvantages relative to iron sights. Standard doctrine with iron sights is to focus the eye on the front sight and align it with the resulting blur of the target and the rear sight; most shooters have difficulty doing this, as the eye tends to be drawn to the target, blurring both sights. Gun users over 30 years of age with keen eyesight will find it harder to keep the target, front sight element and rear sight element well enough into focus for aiming purposes as human eyes gradually lose focusing flexibility with rising age, due to presbyopia. Telescopic sights allow the user to focus on both the crosshair and the target at the same time, as the lenses project the crosshair into the distance (50 m or yd for rimfire scopes, 100 m or yd more for centerfire calibers). This, combined with telescopic magnification, clarifies the target and makes the target stand out against the background. The main disadvantage of magnification is that the area to either side of the target is obscured by the tube of the sight. The higher the magnification, the narrower the field of view in the sight, and the more area that is hidden. Rapid fire target shooters use reflex sights, which have no magnification; this gives them the best field of view while maintaining the single focal plane of a telescopic sight. Telescopic sights are expensive, and require additional training to align. Sight alignment with telescopic sights is a matter of making the field of vision circular to minimize parallax error. For maximum effective light-gathering and brightest image, the exit pupil should equal the diameter of the fully dilated iris of the human eye about 7mm, reducing with age.[edit] Military

Looking through a USMC sniper rifle's scope at a practice range Camp Hansen.

seen at 5x zoom

seen at 25x zoomThe P4 stadiametric rangefinding reticle as used in the Schmidt & Bender 5-25x56 PM II LP telescopic sight.

I.O.R. LPS 4x6 TIP2 reticle, the bottom-left corner can be used to determine the distance from a 170 cm tall target.

Dual combat sighting system: ZF 3x4 optical sight topped with red dot sight as used on German G36A1 assault rifles.Though they had been used as early as the 1850s on rifles, and even earlier for other tasks, until the 1980s, when optical device and assault rifle combinations such as the Austrian Steyr AUG and the British SUSAT mounted on the SA80, became standard issue, military use of telescopic sights was restricted to snipers because of the fragility and expense of optical components. Additionally the glass lenses are prone to breakage, and environmental conditions such as condensation, precipitation, dirt, and mud obscure external lenses. The scope tube also adds significant bulk to the rifle. Snipers generally used moderate to high magnification scopes with special reticles that allow them to estimate range to the target. Since the 1990s many other armed forces have adopted optical devices for general issue to infantry units and the rate of adoption has increased as the cost of manufacture has fallen.Telescopic sights provide some tactical disadvantages. Snipers rely on stealth and concealment to get close to their target. A telescopic sight can hinder this because sunlight may reflect from the lens and a sniper raising his head to use a telescopic sight might reveal his position. The famous Finnish sniper Simo Hyh preferred to use iron sights rather than telescopic sights to present less of a target. Harsh climate can also cause problems for telescopic sights as they are less rugged than iron sights. Many Finnish snipers in WWII used iron sights heavily because telescopic sights did not cope with very cold Finnish winters.The market for military telescopic sights intended for military long-range shooting is highly competitive. Several high end optics manufacturers are constantly adapting and improving their telescopic sights to fulfill specific demands of military organizations. Two European companies that are active this field are Schmidt & Bender and Zeiss/Hensoldt. American companies that are also very active in this field are Nightforce, U.S. Optics Inc. and Premier Reticles.[citation needed] These high end sighting components generally cost 1500 / $ 2000 or more. Typical options for military telescopic sights are reticle illumination for use under adverse light circumstances and the presentation of scope settings or ballistic relevant environmental measurements data to the operator through the sights ocular. Military organizations also are a main driving force behind the development of ever more versatile mil-dot reticles,[citation needed] the US Marine Corps specified for their 7000 USMC M8541 Premier/Schmidt & Bender 3-12x50 PM II LP telescopic sights.[citation needed] Other range finding reticle variations like Schmidt & Bender's P4L (Fine) reticule, which uses mil-hash marks instead of mil-dots for ranging purposes, also were developed on request of active snipers and other long-range field shooters.[citation needed]The former Warsaw Pact members produce military telescopic sights for their designated marksmen and developed a range finding reticle based on the height of an average human. The reticle used in the Romanian I.O.R. LPS 4x6 TIP2 4x24 rifle scope is calibrated for ranging a 1.7 m tall target from 200 m to 1000 m. This Romanian scope shares the basic design and stadiametric rangefinder found in the reticle of the original Russian PSO-1 and POSP scope series. The target base has to be lined up on the horizontal line of the range-finding scale and the target top point has to touch the upper (dotted) line of the scale without clearance. The digit under which this line up occurs determines the distance to the target.The Israeli military began widespread use of telescopic sights by ordinary infantrymen to increase hit probability (especially in dim light) and extend effective range of standard issue infantry rifles. Palestinian militants in the al Aqsa Intifada likewise found that adding an inexpensive scope to an AK-47 increased its effectiveness.Today, several militaries issue telescopic sights to their infantry, usually compact, low-magnification sights suitable for snap-shooting. The US military issues the Advanced Combat Optical Gunsight (ACOG), designed to be used on the M16 rifle and M4 carbine. They also use the non-telescopic Aimpoint CompM2 reflector (reflex) sight and the EOTech 553 holographic weapon sight.[citation needed] American soldiers in Iraq and Afghanistan frequently purchase their own combat optics and carry them from home. The British army fields the SA80 rifle with the SUSAT 4 optical sight as standard issue. The Canadian Forces standard C7 rifle has a 3.4 Elcan C79 optical sight. Both Austria and Australia field variants of the Austrian Steyr AUG which has built an integral 1.5x optical sight since its deployment in the late 1970s. The German Army G36 assault rifles have a more or less built in dual combat sighting system consisting of a ZF 3x4 telescopic sight combined with an unmagnified electronic red dot sight. The dual combat sighting system weighs 30 gr (1oz) due to a housing made out of glass fibre reinforced polyamide. All German G36 rifles are adapted to use the Hensoldt NSA 80 II third-generation night sight, which clamps into the G36 carry handle adapter in front of the optical sight housing and mates with the rifle's standard dual combat sighting system.SA80H&KG36AK47FAMASM4A1