The earliest firearms had no firing mechanisms. The user drove a slow-burning match through a touchhole in the rear of the gun. Although tremendously powerful for its time, they were not particularly accurate because the shooter often had to take his eyes of the target in order to fire the gun, or have a second soldier ignite it for him (although the experts for Vlad the Impaler and the Ming Warriors were shown to accurately fire their respective hand cannons unaided). Neither the amount of gunpowder nor the size of the projectile dimensions were controlled, resulting in inaccuracy due to windage, the difference in diameter between the bore and shot.
Matchlocks were the earliest and simplest firing mechanisms developed. A piece of burning cord, known as a "match" was clamped in the end of an S-shaped piece of steel known as a serpentine. When the trigger (often little more than a lever) was pulled, the match was brought to the open end of the touch hole, which contained a small amount of gunpowder that ignited the main charge of gun powder in the barrel. The match frequently needed to be relit.
The Wheellock was a significant improvement over the matchlock in terms of convenience and safety, as it eliminated the need to keep a smoldering match in close proximity to loose gunpowder. It operated using a small wheel much like that on a modern cigarette lighter which was wound up with a key before use. When the trigger was pulled, the wheel spun against a flint, creating a shower of sparks that ignited the gunpowder in the touch hole. The complexity of this system made the wheellock expensive and difficult to manufacture in large numbers, and wheellock firearms were never widely adopted.
The flintlock used a sharpened piece of flint clamped in the jaws of the cock, which struck a steel plate known as the "frizzen", creating the spark necessary to ignite the gun powder. Simpler than the wheellock and more reliable than the matchlock, the flintlock was widely adopted in the 17th Century. The cock had to be manually reset after each firing, and the flint needed to be periodically replaced due to wear from continually striking the frizzen.
Percussion caps, introduced in the mid-19th Century, were a dramatic improvement over the flintlock. The small primer charge used in all previous firearms was replaced by a self-contained explosive charge contained in a brass "cap". The cap was fastened to the touch hole of the gun and was ignited by the impact of the gun's hammer (which functioned like the cock used in flintlocks, except it didn't clamp to anything). The touch hole was no longer exposed to the elements, making the percussion cap mechanism considerably safer, far more weatherproof, and vastly more reliable, as the exposed primer charge had long been a source of misfires in earlier guns.
A firearm's action is the physical mechanism that manipulates cartridges and/or seals the breech, and is also used to describe the method in which cartridges are loaded, locked, and extracted from the mechanism.
A break-action is a firearm where the barrels are hinged and can be "broken open" to expose the breech. Example, Sawed-off shotgun.
A revolver house cartridges in a rotary cylinder and advances them in-line with the bore before each shot. Although revolvers are mostly handguns, there have been rifles and shotguns to use a revolving cylinder. Example, Colt revolver.
In bolt-action firearms, the bolt is operated manually by opening and closing the breech with a small handle. As the handle is operated, the bolt is unlocked, the breech is opened, the spent shell casing is withdrawn and ejected, the firing pin is cocked, and finally a new round/shell (if available) is placed into the breech and the bolt closed. Example, 1896 Krag Carbine.
In a lever-action gun, a lever located near the trigger guard (often incorporating the trigger guard itself) is used to load fresh cartridges into the chamber when the lever is worked. Example, Winchester rifle.
Most commonly seen on shotguns, the handgrip is pumped backwards to eject a spent round of ammunition and then forward to chamber a new round. Example, Mossberg 500 Shotgun.
Blowback operation is a system in which semi-automatic and fully automatic firearms operate through the energy created by combustion in the chamber and bore acting directly on the bolt face through the cartridge. Example, Mini Uzi.
Recoil operation uses the force of the gun's recoil to provide the energy to cycle the round. Example, Glock 19.
In gas-operation, a portion of high pressure gas from the cartridge being fired is used to extract the spent case and chamber a new cartridge.
Short-Stroke Gas PistonEdit
In short-stroke, the gas piston goes less distance as the operating stroke of the action parts. Example, HK G36.
Long-Stroke Gas PistonEdit
In long-stroke, the gas piston goes the same distance as the operating stroke of the action parts. Example, AK-47.
In direct impingement, there is no piston, and the gas acts directly on the action parts. Example, M16.
Types of FirearmsEdit
Handguns are firearms which are designed to be supported and operated using only one hand, although the other hand is often used to support the shooting hand. They typically have a shorter range, smaller magazine, and a slower rate of fire than larger guns, which limits them to being secondary weapons
Pistols are handguns in which the chamber is integral with the barrel. The earliest handguns were single-shot pistols. Most pistols today are magazine fed, usually with the magazine located in the handle, and are semi-automatic, although there are exceptions.
Revolvers are handguns with a revolving cylinder with multiple chambers. As the hammer is cocked, the cylinder revolves to align the next chamber and round with the hammer and barrel. Each chamber needs to be loaded separately, making revolvers slower to reload than magazine-fed guns.
Muskets are muzzle-loaded, smoothbore long guns fired from the shoulder. Because the musket is a smoothbore gun, it is not as accurate as a rifle. For this reason, the musket is essentially obsolete and is generally only used in reenactments.
Originally called rifled muskets, the rifle gets its name from the rifling (spiral grooves cut into the barrel) that cause the bullet to spin, giving it a straighter trajectory, and as a result, greater distance and accuracy.
A carbine is a shortened version of a rifle or musket, making it smaller and lighter, and therefore more maneuverable in tight quarters, although the shorter barrel results in a lower projectile velocity and shorter effective range.
Assault rifles are selective fire (selectable between semi-automatic and fully automatic) rifles which use intermediate rounds. They are the standard infantry weapon in most modern armies.
Sniper rifles are precision rifles used to ensure more accurate placement of bullets at longer ranges than other small arms. They are built for optimum levels of accuracy, fitted with a telescopic sight and chambered for a military centerfire cartridge.
A shotgun is a smoothbore gun 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. Because the individual shot spread apart after leaving the barrel, shotguns have relatively short effective ranges, but much larger zones of trauma than a rifle or handgun would.
A machine gun is a fully automatic mounted or portable firearm, usually designed to fire to fire rounds in quick succession from an ammunition belt or large-capacity magazine, typically at a rate of several hundred rounds per minute.
A submachine gun is an automatic firearm designed to fire pistol-sized cartridges. They range in size from just slightly larger than a pistol to the size of carbines.
Light Machine GunsEdit
Light machine guns are designed to be employed by an individual soldier, with or without an assistant, as an infantry support weapon. Light machine guns are often used as squad automatic weapons.
Heavy Machine GunsEdit
The term "heavy machine gun" originally referred to weapons that were too large and cumbersome to be moved quickly and were generally used for static defense. In more recent times, it refers to large-caliber (.50 or 12.7 mm) machine guns that were designed to provide an increased degree of range, penetration and destructive power against vehicles, buildings, aircraft and light fortifications.