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90-568: The initial MAS-49 semi-automatic rifle was produced in limited quantities (20,600 units), whereas the shorter and lighter variant, the MAS-49/56, was mass-produced (275,240 units) and issued to all branches of the French military. Overall, the MAS-49 and 49/56 rifles gained the reputation of being accurate, reliable and easy to maintain in adverse environments. All the MAS-49 and 49/56 rifles feature

180-408: A White-tailed deer buck by adjusting magnification until the area between the backbone and the brisket fits between the crosshairs and the top thick post of the reticle. Once that is done, the range be read from the scale printed on the magnification adjustment ring. Although FFP designs are not susceptible to magnification-induced errors, they have their own disadvantages. It's challenging to design

270-500: A mathematical formula "[Target size] ÷ [Number of mil intervals] × 1000 = Distance", the user can easily calculate the distance to a target, as a 1-meter object is going to be exactly 1 milliradian at a 1000-meter distance. For example, if the user sees an object known to be 1.8 meters tall as something 3 mils tall through the telescopic sight, the distance to that object will be 600 meters (1.8 ÷ 3 × 1000 = 600). Some milling reticles have additional marking patterns in

360-602: A scope informally, is an optical sighting device based on a refracting telescope . It is equipped with some form of a referencing pattern – known as a reticle – mounted in a focally appropriate position in its optical system to provide an accurate point of aim. Telescopic sights are used with all types of systems that require magnification in addition to reliable visual aiming, as opposed to non-magnifying iron sights , reflector (reflex) sights , holographic sights or laser sights , and are most commonly found on long-barrel firearms , particularly rifles, usually via

450-491: A scope mount . Similar devices are also found on other platforms such as artillery , tanks and even aircraft . The optical components may be combined with optoelectronics to add night vision or smart device features. 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. In

540-450: A zoom mechanism behind the erector lenses . Variable-power sights offer more flexibility when shooting at varying distances, target sizes 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 "3-9×40" means a telescopic sight with variable magnification between 3× and 9×, and

630-416: A 40 mm objective lens. The ratio between the maximum and minimum magnifications of a variable-power sight is known as its "zoom ratio". 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 4×81 (4× magnification) sight would be presumed to have

720-429: A brighter sight picture than a 2.5×70 (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 4×81 would have an objective 36 mm diameter and the 2.5×70 should be approximately 21 mm (relative luminosity

810-445: A combination of the above, that are added to a crosshair to help with easier aiming. Many modern reticles are designed for (stadiametric) rangefinding purposes. Perhaps the most popular and well-known ranging reticle is the mil-dot reticle , which consists of a duplex crosshair with small dots marking each milliradian (or "mil") intervals from the center. An alternative variant uses perpendicular hash lines instead of dots, and

900-474: A comparatively light inertial strike. The NATO military alliance uses NATO specific standardization agreements (STANAGs) that define the minimal and maximal allowed primer sensitivity for small arms ammunition. For 5.56×45mm NATO ammunition STANAG 4172, among a considerable number of technical requirements, specifies the permissible primer sensitivity range for 5.56×45mm NATO ammunition. Spring-loaded firing pins may move further forward than expected during

990-405: A complex production process. The main tube of telescopic sights varies in size, material, the applied production process and surface finish. The typical outside diameters vary between 19.05 mm (0.75 in) and 40 mm (1.57 in), although 25.4 mm (1 in), 30 mm and recently 34 mm are by far the most common sizes. The internal diameter of the main tube influences

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1080-662: A crisp tactile feedback corresponding to each graduation of turn, often accompanied by a soft but audible clicking sound. Each indexing increment is thus colloquially called a "click", and the corresponding angular adjustment of the optical axis is known as the click value . The most commonly seen click values are 1 ⁄ 4   MOA (often expressed in approximations as " 1 ⁄ 4  inch at 100 yards") and 0.1  mil (often expressed as "10 mm at 100 meters"), although other click values such as 1 ⁄ 2  MOA, 1 ⁄ 3  MOA or 1 ⁄ 8  MOA and other mil increments are also present on

1170-445: A first focal plane reticle expands and shrinks along with the rest of the image as the magnification is adjusted, while a second focal plane reticle would appear the same size and shape to the user as the target image grows and shrinks. In general, the majority of modern variable-power sights are SFP unless stated otherwise. Every European high-end telescopic sight manufacturer offers FFP reticles on variable power telescopic sights, since

1260-470: A fixed magnification factor of 10×, with a 50 mm objective lens. In general terms, larger objective lens diameters, due to their ability to gather a higher luminous flux , provide a larger exit pupil and hence provide a brighter image at the eyepiece . Most early telescopic sights were fixed-power and were in essence specially designed viewing telescopes. Telescopic sights with variable magnifications appeared later, and were varied by manually adjusting

1350-513: A forward position or a magazine loaded with defective ammunition may cause a round to fire every time the bolt closes until the magazine is empty. Shooters must keep the firearm pointed in a safe direction ("downrange") while closing the bolt and chambering a cartridge. If a slamfire does occur, the shooter must do his or her best to hold the firearm securely pointed in a safe direction until it ceases firing. This requires discipline, because untrained shooters may become surprised and instinctively drop

1440-538: A gas cutoff that prevents gas from entering the gas tube from the gas port when firing grenade launching blank ammunition. Attempts were made to replace the MAS-49, in the form of the MAS-54 and the FA-MAS Type 62 , both 7.62×51mm NATO battle rifles , but neither were successful. The MAS-49/56 ended production in 1978 and was replaced with the 5.56×45mm NATO caliber FAMAS bullpup assault rifle . The MAS-49/56

1530-402: A hollow located on the front face of the bolt carrier. The contained forces of the gases move the carrier to the rear against the operating spring pressure with enough momentum to open the bolt, and within a short distance the end of the tube is exposed vent to the atmosphere. The M16 system vents gas from the barrel through a tube and into the body of the bolt carrier where it expands. Rings on

1620-668: A light source to provide an illuminated reticle for low-light condition aiming. In sights such as the SUSAT or Elcan C79 Optical Sight tritium-illuminated reticles are used. The Trijicon Corporation, famous for their ACOG prism sights that are adopted by various assault infantry branches of the United States military , uses tritium in their combat and hunting-grade firearm optics. The tritium light source has to be replaced every 8–12 years, since it gradually loses brightness due to radioactive decay . Slamfire A slamfire

1710-584: A long-eye relief (LER) telescopic sight is the German ZF41 which was used during World War II on Karabiner 98k rifles. An early example of a man-portable sight for low visibility/night use is the Zielgerät (aiming device) 1229 (ZG 1229), also known by its code name Vampir ("vampire"). The ZG 1229 Vampir was a Generation 0 active infrared night vision device developed for the Wehrmacht for

1800-512: A rail on the left side of their receivers to accommodate a designated rifle scope . The MAS-49 and MAS-49/56 were replaced as French service rifles by the FAMAS assault rifle in 1979. The MAS-49 arrived after a series of small, distinct design improvements. Today, this might be termed spiral development , where small elements are changed with successive models, rather than large significant changes. The MAS-49 semi-automatic rifle evolved from

1890-672: A rear-locking tilting bolt, as on the M1895 Colt–Browning machine gun , the Browning Automatic Rifle (1918), the MAS-1924 to MAS-1928 experimental semi-auto rifles, and the Russian Simonov SVT-38 (1938) and SVT-40 (1940) rifles. The MAS direct impingement design reduced the number of bolt moving parts to only six: the bolt carrier, then the rear locking tilting bolt which carries the extractor,

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1980-541: A reputation for reliability in conditions of poor maintenance, sometimes being cleaned with nothing more than rags and motor oil. The 49 and 49/56 series could also endure harsh service environments, seeing combat in Algeria, Djibouti , Indochina, French Guiana , and the Battle of Kolwezi . An improved version called the MAS-49/56 was introduced in 1957 and incorporated lessons learned from service in Algeria, Indochina, and

2070-474: A reticle that is visible through the entire range of magnification: a reticle that looks fine and crisp at 24× magnification may be very difficult to see at 6×. On the other hand, a reticle that is easy to see at 6× may be too thick at 24× to make precision shots. Shooting in low light conditions also tends to require either illumination or a bold reticle, along with lower magnification to maximize light gathering. In practice, these issues tend to significantly reduce

2160-703: A round dot, small cross , diamond , chevron and/or circle in the center (in some prism sights and reflex / holographic sights ), or a pointed vertical bar in a " T "-like pattern (such as the famous "German #1" reticle used on the Wehrmacht ZF41 sights during the Second World War , or the SVD -pattern reticle used on the Soviet PSO-1 sights during the Cold War ) that essentially imitates

2250-595: A sight made by gunsmith Morgan James of Utica, New York . Chapman worked with James on the concepts and design of the Chapman-James sight. In 1855, optician William Malcolm of Syracuse, New York began producing his own telescopic sight, used an original design incorporating achromatic lenses such as those used in telescopes, and improved the windage and elevation adjustments. These Malcolm sights were between 3× and 20× magnification (possibly more). Malcolm's sights and those made by Vermont jeweller L. M. Amidon were

2340-447: A stripper clip guide built into the bolt face. Lastly, the MAS-49 and MAS-49/56 are equipped with a rail on the left side of the receiver. It allows for the immediate installation of a "Modele 1953" APX L 806 (SOM) 3.85 power telescopic sight by sliding it into place and then locking it in with a small pressure lever. The MAS-49 and MAS-49/56 are capable of consistently hitting individual man-size targets up to 400 m (1,300 ft) with

2430-781: A target of a known diameter of 16 inches fills just half of the total post-to-post distance (i.e. filling from sight center to post), then the distance to target is approximately 200 yards (180 m). With a target of a diameter of 16 inches 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

2520-518: A telescope to a rifle as a sighting aid, but was unable to mount it sufficiently far forward to prevent the eyepiece impacting with the operator's eye during recoil . In the same year, James Lind and Captain Alexander Blair described a gun which included a telescopic sight. The first rifle sight was created in 1835 -1840. In the book The Improved American Rifle , written in 1844, British-American civil engineer John R. Chapman described

2610-426: A trigger are either spring-loaded or free-floating. Both may move forward during the loading process when the face of the bolt hits the head of the chamber. Although the amount of forward movement is not intended to detonate the primer, slamfires occur when conditions do not match design assumptions. Cartridges which may be entirely satisfactory in manually loaded firearms may be considered defective if they do not meet

2700-417: A typical Leupold brand 16 minute of angle (MOA) duplex reticle (similar to image B) on a fixed-power telescopic sight, the distance from post to post, between the heavier lines of the reticle spanning the center of the sight picture, is approximately 32 inches (810 millimeters) at 200 yards (180 m), or, equivalently, approximately 16 inches (410 millimeters) from the center to any post at 200 yards. If

2790-408: Is a discharge of a firearm occurring as a cartridge is being loaded into the chamber . Some firearms are designed to slamfire, but the term also describes a malfunction of self-loading firearms. Shooters accustomed to firearms requiring trigger activation for discharge may be unprepared for a slamfire discharge. Some military firearms are designed to fire from an open bolt condition to avoid

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2880-404: Is a function of the thickness and hardness of the metal cup containing the detonating explosive. Primers intended to respond to the comparatively light firing pin impact of older or smaller manually-loaded firearms may be initiated by the relatively energetic self-loading process necessary to reliably chamber cartridges. Most military ammunition makes use of hard primers unlikely to be detonated by

2970-409: Is essential that its brightness can be adjusted. A reticle that is too bright will cause glare in the operator's eye, interfering with their 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

3060-406: Is etched onto one of the prism's internal reflection surfaces, which allows an easy way to illuminate the reticle (from the back side of the prism) even when active illumination is turned off. Being optical telescopes , prism sights can focally compensate for a user's astigmatism . Prismatic sights are lighter and more compact than conventional telescopic sights, but are mostly fixed-powered in

3150-465: Is known as the mil-hash reticle . Such graduated reticles, along with those with MOA -based increments, are collectively and unofficially called " milling reticles ", and have gained significant acceptance in NATO and other military and law enforcement organizations. Mil-based reticles, being decimal in graduations, are by far more prevalent due to the ease and reliability of ranging calculations with

3240-675: Is that admirable secret, which, as all other things, appeared when it pleased the All Disposer, at whose direction a spider's line drawn in an opened case could first give me by its perfect apparition, when I was with two convexes trying experiments about the sun, the unexpected knowledge...if I .... placed a thread where that glass [the eyepiece] would best discern it, and then joining both glasses, and fitting their distance for any object, I should see this at any part that I did direct it to ..." — William Gascoigne In 1776, Charles Willson Peale collaborated with David Rittenhouse to mount

3330-722: Is the MAS-38/39. It was successfully tested in March 1939, just before World War II, and followed in May 1940 by the nearly identical MAS 1940. Similar direct impingement designs include the Swedish semi-automatic Ag m/42 adopted in 1942, and the US M16 select-fire rifle adopted in 1963. In the AG42B and MAS systems, gas is vented from a port on top of the barrel through a small diameter tube to

3420-470: Is the square of the exit pupil as measured in mm; a 36 mm objective lens diameter divided by the 4× magnification gives an exit pupil of 9 mm; 9×9=81) A relatively new type of telescopic sight, called prismatic telescopic sight , prismatic sight or " prism scope ", replaces the image-erecting relay lenses of a traditional telescope with a roof prism design commonly found in compact binoculars , monoculars and spotting scopes . The reticle

3510-463: Is usually provided by a battery -powered LED , though other electric light sources can be used. The light is projected forward through the sight, and reflects off the back surface of the reticle. Red is the most common colour used, as it least impedes the shooter's natural night vision . This illumination method can be used to provide both daytime and low-light conditions reticle illumination. Radioactive isotopes such as tritium can also be used as

3600-594: The Cartesian coordinate system , which the shooter can use as a simple reference for rough horizontal and vertical calibrations. Crosshair reticles typically do not have any graduated markings, and thus are unsuitable for stadiametric rangefinding . However some crosshair designs have thickened outer sections that help with aiming in poor contrast situations when the fine crosshair center cannot be seen clearly. These "thin-thick" crosshair reticles, known as duplex reticles , can also be used for some rough estimations if

3690-662: The MAS-49 replaced the diverse collection of aging bolt-action rifles ( MAS-36 , Lee–Enfield No4 , M1903A3 Springfield , U.S. M1917 , Berthier , and K98k ) which had been absorbed into French service after the end of World War II . It saw significant service with French troops in the latter stages of the First Indochina War , as well as during the Algerian War and the Suez Crisis . The MAS-49 series had

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3780-495: 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. Telescopic sights are classified in terms of the optical magnification (i.e. "power") and the objective lens diameter . For example, "10×50" would denote

3870-519: The eyepiece , since the image illuminance is often sufficient without needing an enlarged objective bell to enhance light-gathering. Most LPVOs have reticles mounted at the second focal plane, but recently first-focal plane LPVOs have become popular, especially those with high zoom ratios above 6×. LPVOs are also informally referred to as " AR scopes" or " carbine scopes", due to the recently increasing popularity of modern sporting rifles and compact "tactical"-style semi-automatic rifles used among

3960-501: The law enforcement , home defense and practical shooting enthusiasts crowd. Telescopic sights are usually designed for the specific application for which they are intended. Those different designs create certain optical parameters. Those parameters are: Because a typical telescopic sight has several optical elements with special characteristics and several air-to-glass surfaces, telescopic sight manufacturers use different types of optical coatings for technical reasons and to improve

4050-475: The Suez Crisis. The rifle was shortened and lightened to improve mobility for mechanized and airborne troops, and a knife bayonet was added. The MAS-49 built-in rifle grenade launcher was replaced by a combination compensator / rifle grenade launcher that fired NATO -standard 22mm rifle grenades . The rifle also incorporates an integral grenade launching sight that is attached to the front sight block and

4140-461: The adjustable peep sight and up to 800 m (2,600 ft) with the APX L 806 telescopic sight. The bore is counter sunk at the muzzle to protect the rifling and preserve accuracy. The barrel is freely floating. Syria contracted with MAS for 6,000 MAS-49 rifles. These rifles, along with 12,000 MAS-36 rifles and a production facility for 7.5×54mm ammunition were delivered in the early 1950s. The MAS-49

4230-437: The aim high and away from the target, are therefore called holdover reticles . Such aiming technique can quickly correct for ballistic deviations without needing to manually readjust the sight's zero, thus enabling the shooter to place rapid, reliably calibrated follow-up shots. When shooting at extended distances , the farther the target, the greater the bullet drops and wind drifts that need to be compensated. Because of this,

4320-412: The amount of "lost" light present inside the telescopic sight which would otherwise make the image appear hazy (low contrast). A telescopic sight with good optical coatings may yield a brighter image than uncoated telescopic sights with a larger objective lens, on account of superior light transmission through the assembly. The first transparent interference-based coating Transparentbelag (T) used by Zeiss

4410-451: The amount of space within which the relay lens group and other optical elements can be mounted, the maximum size of the erector tube, and the maximum angular ranges for elevation and windage adjustments. Telescopic sights intended for long-range and/or low-light usage generally feature larger main tube diameters. Besides optical, spatial and attainable range of elevation and windage adjustments considerations, larger diameter main tubes offer

4500-532: The available magnification range on FFP sights compared to SFP, and FFP sights are much more expensive compared to SFP models of similar quality. Most high-end optics manufacturers leave the choice between a FFP or SFP mounted reticle to the customer or have sight product models with both setups. Variable-power telescopic sights with FFP reticles have no problems with point of impact shifts. Variable-power telescopic sights with SFP reticles can have slight point-of-impact shifts through their magnification range, caused by

4590-476: The bolt body form a seal and the expanding gases move the bolt carrier to the rear, which starts the bolt opening cycle. The spent gases then vent through now exposed holes in the side of the bolt carrier. The MAS system has the advantage of not depositing gas fouling on the bolt itself, a separate part located underneath the bolt carrier. All the French MAS 7.5mm semi-automatic rifles mentioned herein feature

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4680-406: The bolt into an open position while ejecting the empty case. More conventional self-loading firearms begin this cycle with a cartridge already in the chamber and await activation of the trigger to allow the firing pin to impact the primer, causing discharge and loading another cartridge into the chamber. The first cartridge must be loaded from the magazine by manually pulling back and then releasing

4770-437: The bottom two quadrants , consisting of elaborate arrays of neatly spaced fine dots, "+" marks or hashed lines (usually at 0.2  mil or ½  MOA intervals), to provide accurate references for compensating bullet drops and wind drifts by simply aiming above (i.e. "hold [the aim] over" the target) and upwind of the target (i.e. deflection shooting , or " Kentucky windage "). This type of reticles, designed to hold

4860-475: The coating, the character of the image seen in the telescopic sight under normal daylight can either "warmer" or "colder" and appear either with higher or lower contrast. Subject to the application, the coating is also optimized for maximum color fidelity through the visible spectrum . A common application technique is physical vapor deposition of one or more superimposed very thin anti-reflective coating layer(s) which includes evaporative deposition , making it

4950-414: The commercial and military and law enforcement sights. Older telescopic sights often did not offer internal windage and/or elevation adjustments in the telescopic sight. In case the telescopic sight lacked internal adjustment mechanisms adjustable mounts are used (on the scope rings or the mounting rail itself) for sighting-in . Telescopic sights come with a variety of different reticles , ranging from

5040-444: The design specifications of self-loading firearms. Primer depth is very important in centerfire ammunition . Most cartridges are assembled with the exposed surface of the primer a specified distance deeper than the base of the cartridge in contact with the bolt face. Primers with insufficient depth may be detonated by the normal amount of firing pin movement as the cartridge is chambered by forward bolt movement. Primer response to impact

5130-454: The ejector and the firing pin, and lastly the recoil spring. It takes only a few seconds to disassemble the entire bolt mechanism for cleaning. The same 10-round detachable magazine fits the MAS-44, MAS-49 and MAS-49/56 rifles. The earlier MAS-40 (1940) rifle had a 5-round magazine within the receiver, as on the bolt action MAS-36 rifle . The rifle can still be fed by stripper clips , and have

5220-427: The firearm as soon as it begins firing. Aside from the dangers of any accidental discharge, an out-of-battery ignition may occur if a round slamfires before it is completely secured in the chamber. The firearm may be damaged or destroyed by a breech explosion potentially injuring the shooter and bystanders. Pipe guns use a free floating gun barrel with a rimmed cartridge (usually a shotgun shell ) inserted in

5310-418: The firearm chamber may deform the cartridge rim enough to function as a firing pin during the self-loading process. Unintended slamfires are dangerous, and recoil may cause shooters to lose control of light firearms with conditions causing sequential slamfires if a normally semi-automatic firearm "goes full-auto " unexpectedly. A single defective cartridge may cause a single slamfire, but a firing pin stuck in

5400-446: The front post on iron sights . However, most reticles have both horizontal and vertical lines to provide better visual references. The crosshair is the most rudimentary reticle, represented as a pair of smooth, perpendicularly intersecting lines in the shape of a " + ", and the crosshair center is used for aiming the weapon. The crosshair lines geometrically resemble the X- and Y-axis of

5490-418: The gas shutoff pin with a tapped set screw for gas adjustment. Commercial 7.5×54mm "French" ammunition made in countries other than France for current distribution has been known to produce burst fire (2 or 3 rounds at a time) because of more sensitive primers. The original heavy steel firing pins on the MAS-49 and 49/56 can be replaced by commercial titanium firing pins which are much lighter and generally cure

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5580-418: The highest power. Some long-range shooters and military snipers use fixed-power telescopic sights to eliminate this potential for error. Some SFP sights take advantage of this aspect by having the shooter adjust magnification until the target fits a certain way inside the reticle and then extrapolate the range based on the power adjustment. Some Leupold hunting sights with duplex reticles allow range estimation to

5670-604: The human eye luminous efficiency function variance. Maximal light transmission around wavelengths of 555 nm ( green ) is important for obtaining optimal photopic vision using the eye cone cells for observation in well-lit conditions. Maximal light transmission around wavelengths of 498 nm ( cyan ) is important for obtaining optimal scotopic vision using the eye rod cells for observation in low light conditions. These allow high-quality 21st century telescopic sights to practically achieve measured over 90% light transmission values in low light conditions. Depending on

5760-402: The image they produce. Lens coatings can increase light transmission, minimize reflections, repel water and grease and even protect the lens from scratches. Manufacturers often have their own designations for their lens coatings. Anti-reflective coatings reduce light lost at every optical surface through reflection at each surface. Reducing reflection via anti-reflective coatings also reduces

5850-434: The late 1630s, English amateur astronomer William Gascoigne was experimenting with a Keplerian telescope and left it with the case open. Later he found that a spider had spun its web inside the case, and when he looked through the telescope he found that the web was in focus with distant objects. Gascoigne realised that he could use this principle to make a telescopic sight for use in his astronomical observations. "This

5940-449: The loading process if the restraining spring is broken or weakened by age. As rust, dirt, fouling, or inappropriately viscous lubricants accumulate in the firing pin channel, both free-floating and spring-loaded firing pins may be held in a forward position protruding from the bolt face. While rust prevention is important, wet lubricants can trap carbon and other pollutants from burning propellant, so avoidance of excess lubrication reduces

6030-432: The low magnification range (1–4×, 1–6×, 1–8×, or even 1–10×) are known as low-power variable optics or LPVOs . These telescopic sights are often equipped with built-in reticle illumination and can be dialed down to 1× magnification. As low magnifications are mostly used in close- and medium ranges, LPVOs typically have no parallax compensation (though a few rare models do) and have a completely cylindrical shape ahead of

6120-614: The low magnification ranges (usually 2×, 2.5×, 3× or more commonly 4×, occasionally 1× or 5× or more), suitable for shooting at short/medium distances. One of the best known examples is the battle-proven Trijicon ACOG used by the USMC , US Army, and USSOCOM , although variable-magnification prism sights do also exist, such as the ELCAN Specter DR/TR series used by the Canadian Army . Variable-zoom telescopic sights in

6210-547: The oldest type of reticles and are made out of metal wire or thread, mounted in an optically appropriate position in the telescopic sight's tube. Etched reticles are an optic element, often a glass plate, with inked patterns etched onto it, and are mounted as an integrated part of the lightpath . When backlit through the ocular, a wire reticle will reflect incoming light and cannot present a fully opaque (black) reticle with high contrast. An etched reticle will stay fully opaque (black) if backlit. Reticle patterns can be as simple as

6300-468: The optical needs of European hunters who live in jurisdictions that allow hunting at dusk, night and dawn differ from hunters who traditionally or by legislation do not hunt in low light conditions. The main disadvantage of SFP designs comes with the use of range-finding reticles such as mil-dot. Since the proportion between the reticle and the target is dependent on selected magnification, such reticles only work properly at one magnification level, typically

6390-511: The original 7.5x54 caliber. The direct impingement gas system was first applied in 1901 to a 6 mm (0.24 in) semi-automatic experimental rifle (the ENT B-5 ) designed by Rossignol for the French military. Although several experimental prototypes using a tilting bolt and direct impingement had been tested by MAS since 1924, the immediate precursor to the MAS 7.5mm semi-automatic rifle series

6480-912: 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 accuracy-oriented users, who wish to use their telescopic sight trouble-free at several magnification levels, often opt for FFP reticles. Around the year 2005 Zeiss was the first high-end European telescopic sight manufacturer who brought out variable magnification military grade telescopic sight models with rear SFP mounted reticles. They get around impermissible impact shifts by laboriously hand-adjusting every military grade telescopic sight. The American high-end telescopic sight manufacturer U.S. Optics Inc. also offers variable magnification military grade telescopic sight models with SFP mounted reticles. Either type of reticle can be illuminated for use in low-light or daytime conditions. With any illuminated low-light reticle, it

6570-709: The possibility to increase the tube walls thickness (hence a more robust sight) without sacrificing a lot of internal diameter. A telescopic sight can have several manual adjustment controls in the form of control knobs or coaxial rings. All telescopic sights have the first three (diopter, elevation, windage) adjustment controls, and the fourth (magnification) control is offered on variable-power sights. The remaining two adjustments are optional and typically only found on higher-end models with additional features. The windage and elevation adjustment knobs (colloquially called "tracking turrets") often have internal ball detents to help accurately index their rotation, which provide

6660-420: The problem of burst fire on these weapons. It is also possible to prevent these slamfires by shortening the firing pin by approximately 0.5 mm (0.020 in), or by modifying the bolt to accommodate a firing pin return spring.Some users have been able to convert 20 round FN FAL magazines to work in the 7.62mm NATO guns and 25 round FM 24/29 light machine gun or 35 round Reibel machine gun magazines for

6750-740: The prototype MAS-38/39 and from the MAS-40 , and lastly from the post-war MAS-44 and its minor variants 44A, 44B and 44C. Although 50,000 MAS-44 rifles were ordered in January 1945, only 6,200 were delivered to the French Navy . The MAS-49 was formally adopted by the French Army in July 1949. Its final form the MAS 49-56 was the French service rifle until adoption of the FAMAS . As a service rifle ,

6840-528: The reference arrays of holdover reticles are typically much wider at the lower portion, shaping into an isosceles triangle / trapezium that resembles the canopy of a spruce , the ornamental tree traditionally used to make Christmas trees . Holdover reticles therefore are colloquially also known as " Christmas tree reticles ". Well-known examples of these reticles include GAP G2DMR, Horus TReMoR series and H58/H59, Vortex EBR-2B and Kahles AMR. Telescopic sights based on image erector lenses (used to present to

6930-406: The risk of slam fires from firing pins becoming stuck forward. Anything adhering to the tip of a firing pin or the portion of the bolt face behind the primer may cause unexpectedly heavy primer contact during the self-loading process. The larger priming compound distribution area of rimfire ammunition increases the number of locations where dirt or fouling on the bolt face or in the rim portion of

7020-599: The shortening of the barrel to allow rechambering brings the gas vent closer to the chamber hence creating a higher stress on the bolt carrier. In addition to these Century Arms conversions, approximately 250 MAS-49/56 rifles were converted in France to 7.62×51mm NATO for use by the French National Police . These rifles are not known to have the reliability issues that plague the later Century Arms conversions. Some have been able to improve reliability by modifying

7110-409: The simple crosshairs to complex reticles designed to allow the shooter to range a target, to compensate for the bullet drop, and to adjust 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 sight. For example, with

7200-406: The spring-loaded bolt to chamber the cartridge; and unintentional slamfires may occur if the firing pin activates the primer as the first cartridge is being chambered. Unintentional slamfires may also occur during the normal self-loading process following an intended discharge. Control of firing pin movement is the essential difference between cartridge discharge as the bolt closes, or discharge when

7290-657: The standard sharpshooter equipment during the American Civil War . Other telescopic sights of the same period were the Davidson and the Parker Hale . An early practical refracting telescope based telescopic sight was built in 1880 by August Fiedler (of Stronsdorf , Austria ), forestry commissioner of German Prince Reuss . Later telescopic sights with extra long eye relief became available for use on handguns and scout rifles . A historic example of

7380-462: The transition point between thinner and thicker lines are at a defined distance from the center, as seen in designs such as the common 30/30 reticles (both the fine horizontal and vertical crosshair lines are 30  MOAs in length at 4× magnification before transition to thicker lines). There can be additional features such as enlarged center dot (frequently also illuminated ), concentric circle (solid or broken/dashed), chevron , stadia bars, or

7470-578: The trigger is pulled. Firearms designed to discharge as the bolt closes may have a fixed firing pin or a firing pin which moves forward by inertia as forward motion of the bolt ceases when the cartridge is fully chambered, while more conventional firearms are designed to prevent the firing pin from impacting the primer until the trigger is pulled. Some unintentional slamfires are caused by firing pin malfunction, while others may be attributed to defective cartridges with improperly positioned or unexpectedly sensitive primers. Firing pins intended to be activated by

7560-812: The ubiquitous metric units , as each milliradian at each meter of distance simply corresponds to a subtension of 1 millimeter; while MOA-based reticles are more popular in civilian usage favoring imperial units (e.g. in the United States), because by coincidence 1 MOA at 100 yards (the most common sight-in distance) can be confidently rounded to 1 inch. To allow methodological uniformity, accurate mental calculation and efficient communication between spotters and shooters in sniper teams , mil-based sights are typically matched by elevation/windage adjustments in 0.1 mil increments. There are however military and shooting sport sights that use coarser or finer reticle increments. By means of

7650-399: The unintended discharge of a chambered cartridge cooking off in a gun barrel heated by firing previous cartridges. Activating the trigger of such firearms releases the spring-loaded bolt to move forward stripping a cartridge from the magazine into the chamber. The firing pin impacts the primer as the cartridge is chambered, and the energy released by the discharging cartridge returns

7740-551: The user with an upright image) have two planes of focus where a reticle can be placed: at the focal plane between the objective and the image erector lens system (the First Focal Plane (FFP)), or the focal plane between the image erector lens system and the eyepiece (the Second Focal Plane (SFP)). On fixed power telescopic sights there is no significant difference, but on variable power telescopic sights

7830-447: 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 sight, once both the slope of the terrain and the slant range to target are known. There are two main types of reticle constructions: wire reticle and etched reticle . Wire reticles are

7920-478: Was invented in 1935 by Olexander Smakula . A classic lens-coating material is magnesium fluoride , which reduces reflected light from 5% to 1%. Modern lens coatings consist of complex multi-layers and reflect only 0.25% or less to yield an image with maximum brightness and natural colors. Determined by the optical properties of the lenses used and intended primary use of the telescopic sight, different coatings are preferred, to optimize light transmission dictated by

8010-538: Was used until the mid-late 1960s when they were replaced with AK-47 assault rifles. Syrian contract rifles differed from the French service model by having a spike bayonet identical to that of the MAS-36, as well as different stocks and metal parts to incorporate this change. These rifles are dated 1953 and features serial numbers in the F33.000 to F39.000 range. Rifle scope A telescopic sight , commonly called

8100-595: Was withdrawn from service in 1990. Whereas only 20,600 MAS-49 were manufactured, the MAS-49/56 was mass-produced, attaining a total of 275,240 rifles issued between 1957 and 1978. Many MAS-49/56 rifles imported as surplus into the United States were rechambered locally by Century Arms International to fire the 7.62mm NATO round. However several user reports have noted that these particular conversions were often unsatisfactory (resulting in numerous action stoppages and misfires) due to imperfect workmanship. Furthermore,

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