A firearm is any type of gun that uses an explosive charge and is designed to be readily carried and used by an individual. The term is legally defined further in different countries.
A rifle is a long-barreled firearm designed for accurate shooting and higher stopping power, with a barrel that has a helical pattern of grooves (rifling) cut into the bore wall. In keeping with their focus on accuracy, rifles are typically designed to be held with both hands and braced firmly against the shooter's shoulder via a buttstock for stability during shooting. Rifles are used extensively in warfare, law enforcement, hunting and target shooting sports.
A bullet is a kinetic projectile, a component of firearm ammunition that is shot from a gun barrel. They are made of a variety of materials, such as copper, lead, steel, polymer, rubber and even wax; and are made in various shapes and constructions, including specialized functions such as hunting, target shooting, training, and combat. Bullets are often tapered, making them more aerodynamic. Bullet size is expressed by weight and diameter in both imperial and metric measurement systems. Bullets do not normally contain explosives but strike or damage the intended target by transferring kinetic energy upon impact and penetration.
A muzzleloader is any firearm in which the user loads the projectile and the propellant charge into the muzzle end of the gun. This is distinct from the modern designs of breech-loading firearms, in which user loads the ammunition into the breech end of the barrel. The term "muzzleloader" applies to both rifled and smoothbore type muzzleloaders, and may also refer to the marksman who specializes in the shooting of such firearms. The firing methods, paraphernalia and mechanism further divide both categories as do caliber.
The AK-74 is an assault rifle designed by small arms designer Mikhail Kalashnikov in 1974. While primarily associated with the Soviet Union, it has been used by many countries since the 1970s. It is chambered for the 5.45×39mm cartridge, which replaced the 7.62×39mm cartridge of Kalashnikov's earlier automatic weapons for the Soviet Armed Forces.
Indirect fire is aiming and firing a projectile without relying on a direct line of sight between the gun and its target, as in the case of direct fire. Aiming is performed by calculating azimuth and inclination, and may include correcting aim by observing the fall of shot and calculating new angles.
In guns, particularly firearms, but not artillery, where a different definition may apply, caliber is the specified nominal internal diameter of the gun barrel bore – regardless of how or where the bore is measured and whether the finished bore matches that specification. It is measured in inches or in millimeters. In the United States it is expressed in hundredths of an inch; in the United Kingdom in thousandths; and elsewhere in millimeters. For example, a US "45 caliber" firearm has a barrel diameter of roughly 0.45 inches (11.43mm). Barrel diameters can also be expressed using metric dimensions. For example, a "9 mm pistol" has a barrel diameter of about 9 millimeters. Since metric and US customary units do not convert evenly at this scale, metric conversions of caliber measured in decimal inches are typically approximations of the precise specifications in non-metric units, and vice versa.
External ballistics or exterior ballistics is the part of ballistics that deals with the behavior of a projectile in flight. The projectile may be powered or un-powered, guided or unguided, spin or fin stabilized, flying through an atmosphere or in the vacuum of space, but most certainly flying under the influence of a gravitational field.
A gun barrel is a crucial part of gun-type weapons such as small firearms, artillery pieces, and air guns. It is the straight shooting tube, usually made of rigid high-strength metal, through which a contained rapid expansion of high-pressure gas(es) is used to propel a projectile out of the front end (muzzle) at a high velocity. The hollow interior of the barrel is called the bore, and the diameter of the bore is called its caliber, usually measured in inches or millimetres.
Internal ballistics, a subfield of ballistics, is the study of the propulsion of a projectile.
Iron sights are a system of physical alignment markers used as a sighting device to assist the accurate aiming of ranged weapons (such as a firearms, airguns, crossbows, and bows, or less commonly as a primitive finder sight for optical telescopes. Iron sights are the earliest type of sighting device, as it relies completely on the viewer's naked eye, and is distinctly different to optical sights such as telescopic sights, reflector sights, holographic sights, and laser sights, which make use of optical manipulation and/or active illumination.
Accurizing is the process of improving the accuracy and precision of a gun.
Metallic silhouette shooting is a group of target shooting disciplines that involves shooting at steel targets representing game animals at varying distances, seeking to knock the metal target over. Metallic silhouette is shot with large bore rifles fired freehand without support out to 500 meters, and with large bore handguns from the prone position with only body support out to 200 meters. Competitions are also held with airguns and black-powder firearms. A related genre is shot with bow and arrow, the metal targets being replaced with cardboard or foam. The targets used are rams, turkeys, pigs, and chickens, which are cut to different scales and set at certain distances from the shooter depending on the specific discipline.
Boresighting is a method of visually pre-aligning a firearm barrel's bore axis with the target, in order to more easily zero the gunsight. The process is usually performed on a rifle, and can be accomplished either with the naked eye, or with a specialized device called a boresighter.
The term express was first applied to hunting rifles and ammunition beginning in the mid-19th century, to indicate a rifle or ammunition capable of higher than typical velocities. The early express cartridges used a heavy charge of black powder to propel a lightweight, often hollow point bullet, at high velocities to maximize point blank range. Later the express cartridges were loaded with nitrocellulose-based gunpowder, leading to the Nitro Express cartridges, the first of which was the .450 Nitro Express.
Gun laying is the process of aiming an artillery piece or turret, such as a gun, howitzer, or mortar, on land, in air, or at sea, against surface or aerial targets. It may be laying for direct fire, where the gun is aimed similarly to a rifle, or indirect fire, where firing data is calculated and applied to the sights. The term includes automated aiming using, for example, radar-derived target data and computer-controlled guns.
The following are terms related to firearms and ammunition topics.
The 68-pounder cannon was an artillery piece designed and used by the British Armed Forces in the mid-19th century. The cannon was a smoothbore muzzle-loading gun manufactured in several weights, the most common being 95 long cwt (4,800 kg), and fired projectiles of 68 lb (31 kg). Colonel William Dundas designed the 112 cwt version in 1841 and it was cast the following year. The most common variant, weighing 95 cwt, dates from 1846. It entered service with the Royal Artillery and the Royal Navy and saw active service with both arms during the Crimean War. Over 2,000 were made and it gained a reputation as the finest smoothbore cannon ever made.
The bore axis of a firearm is the longitudinal axis through the geometric center of the gun barrel. In a rifled barrel, the projectile will spin around the bore axis as it goes through the barrel.
In ranged weapons such as firearms and artillery pieces, the act of sighting in or sight-in is a preparatory or corrective calibration of the sights with the goal of having the projectile placed on a predictable impact position in relation to the sight picture. The principle of sighting-in is to shift the line of aim until it intersects the parabolic projectile trajectory at a designated point of reference, so when the gun is fired in the future it will repeatably hit where it aims at identical distances of that designated point.
