The Picatinny rail, or Pic rail for short known as a MIL-STD-1913 rail or STANAG 2324 rail, is a military standard rail interface system that provides a mounting platform for firearm accessories. It was used for mounting scopes atop the receivers of larger caliber rifles. Once established, its use expanded to attaching other accessories, such as: iron sights, tactical lights, laser aiming modules, night vision devices, reflex sights, bipods and bayonets; because of their many uses, Picatinny rails and accessories have replaced iron sights in the design of many firearms, they are on the undersides of semi-automatic pistol frames and grips. Their usefulness has led to them being used in airsoft; the rail itself dates from work by the A. R. M. S. Company in the early 1980s and Otto Repa in standardizing the Weaver design. Specifications for the M16A2E4 rifle and the M4E1 carbine received type classification generic in December 1994; these were the M4 modified with new upper receivers where rails replaced hand guards.
The rail is named after the Picatinny Arsenal in New Jersey, tasked in 1992 to develop a standardized mounting system after the U. S. Army was dissatisfied with the contemporary products on the market; the Picatinny team was headed by mechanical designer Gary Houtsma, who took the measurements from 20 or so different Weaver rail products from weapons bunkers at Picatinny and came up with an average set of numbers set on a 45-degree angled surface. Houtsma took the specifications over to the production facility and requested they design a dimensioning style so the rail could be produced and inspected; the factory recognized the similarity of the purposed optics rail to the existing rail design on 105 mm howitzers, so they just scaled down the howitzer rail design and co-opted the production and inspection procedures. The team sent the finished product over to Rock Island Arsenal for review and trial, to the technical data section to determine if it should be a standard or a specification. After it was determined that the new rail should be a standard, not a specification, it was adopted and fielded in 1995 with the designation Mil-STD-1913, dated February 3, 1995.
A metric upgraded version of the Picatinny rail, the STANAG 4694 NATO Accessory Rail, was designed in conjunction with weapon manufacturers like Aimpoint, Colt, FN Herstal and Heckler & Koch, was approved by the NATO Army Armaments Group, Land Capability Group 1 Dismounted Soldier on May 8. 2009. The rail consists of a strip undercut to form a "flattened T" or hexagonal cross-section provided with crosswise slots at intervals interspersed with flats that allow accessories to be slid into place from the end of the rail locked in place, it is similar in concept to the earlier commercial Weaver rail mount used to mount telescopic sights. The Picatinny locking slot width is 0.206 in. The spacing of slot centers is 0.394 in and the slot depth is 0.118 in. Whereas the earlier Weaver rail is modified from a low, wide dovetail rail, the Picatinny rail has a more pronounced angular section. Designed to mount heavy sights of various kinds, a great variety of accessories and attachments are now available and the rails are no longer confined to the rear upper surface of long arms but are either fitted to or machine milled into the upper, side or lower surfaces of all manner of weapons from crossbows to pistols and long arms up to and including anti-materiel rifles.
The only significant difference between the Picatinny rail and the similar Weaver rail are the size and shapes of the slots, where the Picatinny rail has square-bottomed slots while Weaver rails have rounded slots. This means that an accessory designed for a Weaver rail will fit onto a Picatinny rail whereas the opposite might not be possible Weaver rails have a slot width of 0.180 in, but are not consistent in the spacing of slot centers. While some accessories are designed to fit on both Weaver and Picatinny rails, most Picatinny devices will not fit on Weaver rails. From May 2012, most mounting rails are cut to Picatinny standards. Many accessories can be secured to a rail with a single spring-loaded retaining pin. NATO Accessory Rail Warsaw Pact rail, is a rail mount system to connect telescopic sights to rifles Rail Systems Picatinny Rail Specifications
A cartridge is a type of pre-assembled firearm ammunition packaging a projectile, a propellant substance and an ignition device within a metallic, paper or plastic case, made to fit within the barrel chamber of a breechloading gun, for the practical purpose of convenient transportation and handling during shooting. Although in popular usage the term "bullet" is used to refer to a complete cartridge, it is used only to refer to the projectile. Cartridges can be categorized by the type of their primers — a small charge of an impact- or electric-sensitive chemical mixture, located at the center of the case head, inside the rim of the case base, in a sideway projection, shaped like a pin or a lip, or in a small nipple-like bulge at the case base. Military and commercial producers continue to pursue the goal of caseless ammunition; some artillery ammunition uses the same cartridge concept. In other cases, the artillery shell is separate from the propellant charge. A cartridge without a projectile is called a blank.
One, inert is called a dummy. One that failed to ignite and shoot off the projectile is called a dud, one that ignited but failed to sufficiently push the projectile out of the barrel is called a squib; the primary purpose is to be a handy all-in-one for a shot. In modern, automatic weapons, it provides the energy to move the parts of the gun which make it fire repeatedly. Many weapons were designed to make use of a available cartridge, or a new one with new qualities; the cartridge case seals a firing chamber in all directions excepting the bore. A firing pin ignites it; the primer compound deflagrates, it does not detonate. A jet of burning gas from the primer ignites the propellant. Gases from the burning powder expand the case to seal it against the chamber wall; these propellant gases push on the bullet base. In response to this pressure, the bullet will move in the path of least resistance, down the bore of the barrel. After the bullet leaves the barrel, the chamber pressure drops to atmospheric pressure.
The case, elastically expanded by chamber pressure, contracts slightly. This eases removal of the case from the chamber. To manufacture brass for cartidges, a sheet of brass is punched into disks; these disks go through a series of punches and dies and are annealed and washed before moving to the next series of dies. Making bullets involves simular type of maching as for making brass cases; the projectile can be made of anything. Lead is a material of choice because of high density, ductility; the propellant was long gunpowder, still in use, but superseded by better compositions, generically called Smokeless powder. Early primer was fine gunpowder poured into a pan or tube where it could be ignited by some external source of ignition such as a fuse or a spark. Modern primers are shock sensitive chemicals enclosed in a small capsule, ignited by percussion. In some instance ignition is electricity-primed, there may be no primer at all in such design; the case is made of brass because it is resistant to corrosion.
A brass case head can be work-hardened to withstand the high pressures of cartridges, allow for manipulation via extraction and ejection without tearing the metal. The neck and body portion of a brass case is annealed to make the case ductile enough to allow reforming so that it can be reloaded many times. Steel is used in some plinking ammunition, as well as in some military ammunition. Steel is less expensive than brass. Military forces consider small arms cartridge cases to be disposable, one-time-use devices. However, case weight affects how much ammunition a soldier can carry, so the lighter steel cases do have a military advantage. Conversely, steel is more susceptible to contamination and damage so all such cases are varnished or otherwise sealed against the elements. One downside caused by the increased strength of steel in the neck of these cases is that propellant gas can blow back past the neck and into the chamber. Constituents of these gases condense on the chamber wall; this solid propellant residue can make extraction of fired cases difficult.
This is less of a problem for small arms of the former Warsaw Pact nations, which were designed with much larger chamber tolerances than NATO weapons. Aluminum cased; these are not reloaded as aluminum fatigues during firing and resizing. Some calibers have non-standard primer sizes to discourage reloaders from attempting to reuse these cases. Plastic cases are used in shotgun shells and some manufacturers offer polymer centerfire cartridges. Paper had been used in the earliest cartridges. Critical cartridge specifications include neck size, bullet weight and caliber, maximum pressure, overall length, case body diameter and taper, shoulder design, rim type, etc. Ever
A semi-automatic shotgun is a shotgun, able to fire a shell after every trigger pull, without needing to manually chamber another round. These weapons use gas, blowback, or recoil operation to cycle the action, eject the empty shell, load another round. Many semi-automatic shotguns provide an optional manual means of operation such as by pump action or a charging handle. List of shotguns Assault weapon - certain semi-automatic shotguns are classified as assault weapons in some jurisdictions Automatic shotgun Personal defense weapon Semi-automatic firearm Semi-automatic pistol Semi-automatic rifle
In firearms terminology, an action is the mechanism of a breech-loading weapon that handles the ammunition or the method by which that mechanism works. Actions are technically not present on muzzleloaders, as all are single-shot weapons with a closed off breech. Instead, the ignition mechanism is referred to Actions can be categorized in several ways, including single action versus double action, break action versus bolt action, others; the term action can include short and magnum if it is in reference to the length of the rifle's receiver and the length of the bolt. The short action rifle can accommodate a cartridge length of 2.8 in or smaller. The long action rifle can accommodate a cartridge of 3.34 in, the magnum action rifle can accommodate cartridges of 3.6 in, or longer in length. The dropping block are actions wherein the breechblock lowers or "drops" into the receiver to open the breech actuated by an underlever. There are two principal types of dropping block: the falling block. In a tilting block or pivoting block action, the breechblock is hinged on a pin mounted at the rear.
When the lever is operated, the block tilts forward, exposing the chamber. The best-known pivoting block designs are the Peabody, the Peabody–Martini, Ballard actions; the original Peabody rifles, manufactured by the Providence Tool Company, used a manually cocked side-hammer. Swiss gunsmith Friedrich Martini developed a pivoting block action by modifying the Peabody, that incorporated a hammerless striker, cocked by the operating lever with the same single, efficient motion that pivoted the block; the 1871 Martini–Henry which replaced the "trapdoor" Snider–Enfield was the standard British Army rifle of the Victorian era, the Martini was a popular action for civilian rifles. Charles H. Ballard's self-cocking tilting-block action was produced by the Marlin Firearms Company from 1875, earned a superlative reputation among long-range "Creedmoor" target shooters. Surviving Marlin Ballards are today prized by collectors those mounted in the elaborate Swiss-style Schützen stocks of the day. A falling block action is a single-shot firearm action in which a solid metal breechblock slides vertically in grooves cut into the breech of the weapon and actuated by a lever.
Examples of firearms using the falling block action are the Sharps rifle and Ruger No. 1. In a rolling block action the breechblock takes the form of a part-cylinder, with a pivot pin through its axis; the operator rotates or "rolls" the block to close the breech. Rolling blocks are most associated with firearms made by Remington in the 19th century; the hinged block was the earliest metallic-cartridge breechloaders designed for general military issue began as conversions of muzzle-loading rifle-muskets. The upper rear portion of the barrel was filed or milled away and replaced by a hinged breechblock which opened upward to permit loading. An internal angled firing pin allowed the re-use of the rifle's existing side-hammer; the Allin action made by Springfield Arsenal in the US hinged forward. Whereas the British replaced the Snider with a dropping-block Peabody-style Martini action, the US Army felt the trapdoor action to be adequate and followed its muzzleloader conversions with the new-production Springfield Model 1873, the principal longarm of the Indian Wars and was still in service with some units in the Spanish–American War.
A break action is a type of firearm where the barrel are hinged and can be "broken open" to expose the breech. Multi-barrel break action firearms are subdivided into over-and-under or side-by-side configurations for two barrel configurations or "combination gun" when mixed rifle and shotgun barrels are used. Although bolt-action guns are associated with fixed or detachable box magazines, in fact the first general-issue military breechloader was a single-shot bolt action: the paper-cartridge Prussian needle gun of 1841. France countered in 1866 with its superior Chassepot rifle a paper-cartridge bolt action; the first metallic-cartridge bolt actions in general military service were the Berdan Type II introduced by Russia in 1870, the Mauser Model 1871, a modified Chassepot, the Gras rifle of 1874. Today most top-level smallbore match rifles are single-shot bolt actions. Single-shot bolt actions in.22 caliber were widely manufactured as inexpensive "boys' guns" in the earlier 20th century. The eccentric screw action first seen on the M1867 Werndl–Holub and on the Magnum Research Lone Eagle pistol, the breech closure is a rotating drum with the same axis, but offset from the bore.
When locked, a firing pin aligns with the primer and the breech is otherwise solid. When rotated open, a slot in the drum is exposed for feeding of a new round. Though first used on the Werndl-Holub, this action is known as a cannon breech due to its association with the French 75mm Model of 1897 cannon; the French M1897 was, based on William Hubbell's U. S. Patent 149,478; the Ferguson rifle: British Major Patrick Ferguson designed his rifle, considered to be the first military breechloader, in the 1770s. A plug-shaped breechblock was screw-threaded so that rotating the handle underneath would lower a
A shotgun is a firearm, designed to be fired from the shoulder, which uses the energy of a fixed shell to fire a number of small spherical pellets called shot, or a solid projectile called a slug. Shotguns come in a wide variety of sizes, ranging from 5.5 mm bore up to 5 cm bore, in a range of firearm operating mechanisms, including breech loading, single-barreled, double or combination gun, pump-action, bolt-, lever-action, semi-automatic, fully automatic variants. A shotgun was a smoothbore firearm, which means that the inside of the barrel is not rifled but rifled shotgun barrels and slugs become available. Preceding smoothbore firearms, such as the musket, were used by armies in the 18th century; the direct ancestor to the shotgun, the blunderbuss, was used in a similar variety of roles from self-defense to riot control. It was used by cavalry troops because of its shorter length and ease of use, as well as by coachmen for its substantial power. In the 19th century, these weapons were replaced on the battlefield with breechloading rifled firearms, which were more accurate over longer ranges.
The military value of shotguns was rediscovered in the First World War, when American forces used 12-gauge pump action shotguns in close-quarters trench fighting to great effect. Since it has been used in a variety of roles in civilian, law enforcement, military applications; the shot pellets from a shotgun spread upon leaving the barrel, the power of the burning charge is divided among the pellets, which means that the energy of any one ball of shot is low. In a hunting context, this makes shotguns useful for hunting birds and other small game. However, in a military or law enforcement context, the large number of projectiles makes the shotgun useful as a close quarters combat weapon or a defensive weapon. Militants or insurgents may use shotguns in asymmetric engagements, as shotguns are owned civilian weapons in many countries. Shotguns are used for target shooting sports such as skeet and sporting clays; these involve. Shotguns come in a wide variety of forms, from small up to massive punt guns, in nearly every type of firearm operating mechanism.
The common characteristics that make a shotgun unique center on the requirements of firing shot. These features are the features typical of a shotgun shell, namely a short, wide cartridge, with straight walls, operating at a low pressure. Ammunition for shotguns is referred to in the USA as shotshells, or just shells; the term cartridges is standard usage in the United Kingdom. The shot is fired from a smoothbore barrel; the typical use of a shotgun is against small and fast moving targets while in the air. The spreading of the shot allows the user to point the shotgun close to the target, rather than having to aim as in the case of a single projectile; the disadvantages of shot are limited range and limited penetration of the shot, why shotguns are used at short ranges, against smaller targets. Larger shot sizes, up to the extreme case of the single projectile slug load, result in increased penetration, but at the expense of fewer projectiles and lower probability of hitting the target. Aside from the most common use against small, fast moving targets, the shotgun has several advantages when used against still targets.
First, it has enormous stopping power at more than nearly all handguns and many rifles. Though many believe the shotgun is a great firearm for inexperienced shooters, the truth is, at close range, the spread of shot is not large at all, competency in aiming is still required. A typical self-defense load of buckshot contains 8–27 large lead pellets, resulting in many wound tracks in the target. Unlike a jacketed rifle bullet, each pellet of shot is less to penetrate walls and hit bystanders, it is favored by law enforcement for its low penetration and high stopping power. On the other hand, the hit potential of a defensive shotgun is overstated; the typical defensive shot is taken at close ranges, at which the shot charge expands no more than a few centimeters. This means. Balancing this is the fact that shot spreads further upon entering the target, the multiple wound channels of a defensive load are far more to produce a disabling wound than a rifle or handgun; some of the most common uses of shotguns are the sports of skeet shooting, trap shooting, sporting clays.
These involve shooting clay discs known as clay pigeons, thrown in by hand and by machine. Both skeet and trap competitions are featured at the Olympic Games; the shotgun is popular for bird hunting, it is used for more general forms of hunting in semi-populated areas where the range of rifle bullets may pose a hazard. Use of a smooth bore shotgun with a rifled slug or, alternatively, a rifled barrel shotgun with a sabot slug, improves accuracy to 100 m or more; this is well within the range of the majority of kill shots by experienced hunters using shotguns. However, given the low muzzle velocity of slug ammunition around 500 m/s, the blunt, poorly streamlined shape of typical slugs (which cause them to lose
The gauge of a firearm is a unit of measurement used to express the inner diameter of the barrel. Gauge is determined from the weight of a solid sphere of lead that will fit the bore of the firearm and is expressed as the multiplicative inverse of the sphere's weight as a fraction of a pound, e.g. a one-twelfth pound lead ball fits a 12-gauge bore. Thus there are twelve 12-gauge balls per etc.. The term is related to the measurement of cannon, which were measured by the weight of their iron round shot. Gauge is used today in reference to shotguns, though it was used in large double rifles, which were made in sizes up to 2 bore during their heyday in the 1880s, being loaded with black powder cartridges; these large rifles, sometimes called "elephant guns", were intended for use in India and Africa for hunting game. Gauge is abbreviated "ga.", "ga", or "G". An n-gauge diameter means that a ball of lead with that diameter has a mass equal to 1/n part of the mass of the international avoirdupois pound, that is, that n such lead balls could be cast from a pound weight of lead.
Therefore, an n-gauge shotgun or n-bore rifle has a bore diameter of d n = 2 3 4 π 1 l b / n 0.4097 l b / i n 3 3 Explanation: Divide 1 pound by n to find the mass of each one of the balls Divide it by 0.4097 lb/in3 to find the volume of each ball Multiply it by 3/4 and divide it by pi find its cube root to find the radius of each ball Multiply it by 2 to change from radius to diameterThis simplifies to the following formula for the internal diameter of the barrel of an n-gauge shotgun: d n = 1.67 / n 3, or d n = 42.4 / n 3. Given the diameter in inches, the gauge is n = 4.66 / d n 3 The gauge of firearms is determined by. 1 pound / gauge = weight of lead sphere. Caliber of lead sphere is measured; this is essential information for understanding gauges. Since shotguns were not intended to fire solid projectiles, but rather a compressible mass of shot, the actual diameter of the bore can vary; the fact that most shotgun bores are not cylindrical causes deviations from the ideal bore diameter.
The chamber of the gun is larger, to accommodate the thickness of the shotshell walls, a "forcing cone" in front of the chamber reduces the diameter down to the bore diameter. The forcing cone can be as short as a fraction of an inch, or as long as a few inches on some guns. At the muzzle end of the barrel, the choke can constrict the bore further, so measuring the bore diameter of a shotgun is not a simple process, as it must be done away from either end. Shotgun bores are "overbored" or "backbored", meaning that most of the bore is larger than the value given by the formula; this is claimed to improve patterning. The recoil reduction is due to the larger bore producing a slower acceleration of the shot, the patterning improvements are due to the larger muzzle diameter for the same choke constriction, which results in less shot deformation. A 12-gauge shotgun, nominally 18.5 mm, can range from a tight 18 mm to an extreme overbore of 20 mm. Some claim an increased velocity with the overbored barrels, up to 15 m/s, due to the larger swept volume of the overbored barrel.
Once only found in expensive custom shotguns, overbored barrels are now becoming common in mass-marketed guns. Aftermarket backboring is commonly done to reduce the weight of the barrel, move the center of mass backwards for a better balance. Factory overbored barrels are made with a larger outside diameter, will not have this reduction in weight—though the factory barrels will be tougher, since they have a normal barrel wall thickness. Firing slugs from overbored barrels can result in inconsistent accuracy, as the slug may be incapable of obturating to fill the oversized bore; the most common size is 12 gauge, with up to 50% of the overall shotgun market in the United States. The 20 gauge shotgun is favored by shooters uncomfortable with the weight and recoil of a 12 gauge gun, is popular for upland game hunting; the next most popular sizes are.410 bore. The 10 gauge and 16 gauge, while a little less common, are still available in the United States. Shotguns and shells exceeding 10 gauge, such as the 8 and 4 gauge, are rather manufactured and only a few makers of the otherwise large market of shotgun and ammo makers across the United States still produce them.
Shells are black powder paper cartridges as opposed to the plastic or wax cartridge and smokeless powder of today. The 11, 15, 18, 2, 3 gauge shells are rarest of all.
A firearm is a portable gun that inflicts damage on targets by launching one or more projectiles driven by expanding high-pressure gas produced chemically by exothermic combustion of propellant within an ammunition cartridge. If gas pressurization is achieved through mechanical gas compression rather than through chemical propellant combustion the gun is technically an air gun, not a firearm; the first primitive firearms originated in 10th-century China when bamboo tubes containing gunpowder and pellet projectiles were mounted on spears into the one-person-portable fire lance, used as a shock weapon to good effect in the Siege of De'an in 1132. In the 13th century the Chinese invented the metal-barrelled hand cannon considered the true ancestor of all firearms; the technology spread through the rest of East Asia, South Asia, the Middle East, Europe. Older firearms used black powder as a propellant, but modern firearms use smokeless powder or other propellants. Most modern firearms have rifled barrels to impart spin to the projectile for improved flight stability.
Modern firearms can be described in the case of shotguns by their gauge. Further classification may make reference to the type of barrel used and to the barrel length, to the firing mechanism, to the design's primary intended use, or to the accepted name for a particular variation. Shooters aim firearms at their targets with hand-eye coordination, using either iron sights or optical sights; the accurate range of pistols does not exceed 110 yards, while most rifles are accurate to 550 yards using iron sights, or to longer ranges using optical sights. Purpose-built sniper rifles and anti-materiel rifles are accurate to ranges of more than 2,200 yards. Firearms include a variety of ranged weapons and there is no agreed upon definition. Many soldiers consider a firearm to be any ranged weapon that uses gunpowder or a derivative as a propellant. Small arms include handguns and long guns, such as rifles, submachine guns, personal defense weapons, squad automatic weapons, light machine guns; the world's top small arms manufacturing companies are Browning, Colt, Smith & Wesson, Mossberg, Heckler & Koch, SIG Sauer, Walther, ČZUB, Steyr-Mannlicher, FN Herstal, Norinco, Tula Arms and Kalashnikov, while former top producers were Mauser, Springfield Armory, Rock Island Armory under Armscor.
In 2018, Small Arms Survey reported that there are over one billion small arms distributed globally, of which 857 million are in civilian hands. U. S. civilians alone account for 393 million of the worldwide total of civilian held firearms. This amounts to "120.5 firearms for every 100 residents." The world's armed forces control about 133 million of the global total of small arms, of which over 43 percent belong to two countries: the Russian Federation and China. Law enforcement agencies control about 23 million of the global total of small arms; the smallest of all firearms is the handgun. There are two common types of handguns: semi-automatic pistols. Revolvers have "charge holes" in a revolving cylinder. Semi-automatic pistols have a single fixed firing chamber machined into the rear of the barrel, a magazine so they can be used to fire more than one round; each press of the trigger fires a cartridge, using the energy of the cartridge to activate the mechanism so that the next cartridge may be fired immediately.
This is opposed to "double-action" revolvers which accomplish the same end using a mechanical action linked to the trigger pull. Prior to the 19th century all handguns were single-shot muzzleloaders. With the invention of the revolver in 1818, handguns capable of holding multiple rounds became popular. Certain designs of auto-loading pistol appeared beginning in the 1870s and had supplanted revolvers in military applications by the end of World War I. By the end of the 20th century, most handguns carried by military and civilians were semi-automatic, although revolvers were still used. Speaking and police forces use semi-automatic pistols due to their high magazine capacities and ability to reload by removing the empty magazine and inserting a loaded one. Revolvers are common among handgun hunters because revolver cartridges are more powerful than similar caliber semi-automatic pistol cartridges and the strength and durability of the revolver design is well-suited to outdoor use. Revolvers in.22 LR and 38 Special/357 Magnum, are common concealed weapons in j