Glossary of firearms terms

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Safety
Any mechanism designed to prevent accidental firing. The mechanism may be a lever, button or slide and it functions generally by blocking the hammer, sear or trigger until firing is desired. An automatic, mechanical or grip safety denotes any lever or plunger, usually on a weapons grip in a position that allows unconscious squeezing of the mechanism when the weapon is fired. Subsequent relaxing of pressure permits the safety device to reset itself. A thumb safety consists of a sliding button or lever within reach of the thumb of the firing hand.

Safety lock
A device that permits the weapon to be safely carried when loaded and cocked.

Saltpetre
One of the three components of black powder.

Scatter gun
A shotgun with a barrel shortened to spread the shot pattern.

Sear
Pivoted latch in the firing mechanism, operated by the trigger and designed to hold the firing pin or hammer at full or half cock until released. The additional controlled leverage provided by the sear improves the trigger action of the firearm.

Selfloading see Autoloading

Selfloading rifle see Rifle, semiautomatic

Semiautomatic see Autoloading

Semiautomatic revolver see Revolver, semiautomatic

Semiautomatic rifle see Rifle, semiautomatic

Semi pistol grip see Pistol grip

Semi rimmed cartridge see Cartridge, rimless

Serpentine
Of a matchlock firearm, an "S" shaped lever, pivoted in the middle. A slow burning match is inserted into the upper portion so that pressure on the lower portion (trigger) will bring the match into contact with the priming powder in the pan.

Setscrew
1 In mechanics, any screw designed to secure another screw that might become loose through normal use of the mechanism.
2 On a firearm, a screw designed to regulate the pressure required to release the trigger.

Set trigger see Trigger

Shake see Check

Sheath trigger see Trigger

Shell
1 Any projectile propelled by a powder charge.
2 In small arms ammunition, a loaded shotgun cartridge.
3 In small arms ammunition, an empty metallic cartridge case.

Short arm
A hand arm, for example a revolver or pistol.

Short recoil see Action, recoil operated

Shotgun
A smoothbore shoulder arm designed to fire shells containing numerous small shot as projectiles.

Shoulder
The sharply sloping portion of the case of a bottle necked cartridge joining the neck and the body.

Side arm
Any arm designed to be carried on a belt at the side when not in use, including swords, bayonets, pistols and revolvers.

Side plate see Contreplatine

Sight
Any of a variety of devices designed to assist in aiming a firearm. For a rifle a normal sight is attained when the top of the front sight and the target are aligned with the centre of the peep or notch of the rear sight. On a revolver the iron sights are generally rudimentary, designed to aid in pointing the weapon rather than in aiming it. Pairs of sights are termed metallic to distinguish them from optical.

Sight, front
A front sight or foresight generally protrudes above the muzzle of the barrel like a post as in a post sight or like a pyramid as in a pyramidal sight. A notched post sight is called a notch sight. In front sights plain steel is often used though gold or ivory beads may be attached to improve visibility. Sometimes the base is made non-reflecting or a hood as in a hooded sight may cover the post to shield it from the sun.

Sight, leaf
Denotes any metallic sight hinged at its base to allow it to be raised vertically for sighting and lowered horizontally for carrying. A series of leaves may be used, each designed for a particular range.

Sight, orthoptic
A type of leaf sight where one leaf contains a member capable of sliding up and down for range adjustment.

Sight, optical
An optical sight contains in one unit a series of lenses to form an optical aiming system. These sights do not necessarily have telescopic qualities although small arms sights of this type are generally telescopic to enlarge the target. Though mounted at the rear of a firearm, a telescopic sight is not a rear sight since it contains the complete aiming system.

Sight, ramp
A ramp sight may denote either a front sight mounted at the top of a ramp inclined forward and upward, or a rear sight with a member sliding up and down a ramp to change sight elevation.

Sight, rear
The rear sight may occur anywhere between the shooters eye and the foresight. A rear sight mounted on the receiver is called a receiver sight. If the sight involves no tube or aperture through which aim is taken, it is termed open, otherwise the sight is termed aperture. The rear sight may be a notched bar of metal or a disk with a peep hole in the centre, the latter being termed a peep sight.

Sight, tube
Denotes a tube carrying both front and rear sights, but containing no optical system.

Sight, vernier
Any metallic sight adjustable for elevation or windage by means of a vernier (calibrated) screw.

Sighting bar
An instructional device in which eye, rear sight, front sight and target are represented by metal or cardboard plates.

Silencer
A device attached to the muzzle of a firearm to reduce the noise of discharge.

Silhouette
A type of target representing in outline the form of a man prone, kneeling or standing, coloured black or drab olive and used in small arms practice.

Single action see Action, single

Single action revolver see Revolver, single action

Sixgun, Six shooter
Colloquially, a revolver with six chambers in its cylinder.

Slack
Free travel of a trigger before it disengages the hammer or firing pin. Not provided in target weapons or in most sporting arms, slack is a type of safety device used mostly on military firearms.

Slide
1 In semiautomatic pistols, the metal sleeve covering the barrel and top of the action, driven rearward by recoil and returned by spring action. The slide ejects the fired case, cocks the firing mechanism and feeds a fresh cartridge into the chamber.
2 The operating rod in slide action weapons.

Slide action see Action, slide

Sling
On a shoulder arm, a leather or web strap attached to the weapon to assist in carrying the gun and also used to steady it during firing.

Sling swivel
Of a shoulder arm, one of two metal loops fastened to barrel or fore-end and to buttstock, to which the sling is attached.

Slow match see Match

Slug
Any of a variety of metal pieces discharged from a gun.

Small arm
Any weapon capable of being carried on the person and fired without support. In military usage the term includes machine guns and navy 20 and 40 mm automatic weapons.

Small bore
1 In target shooting, a .22 calibre rimfire cartridge employing a lead alloy bullet
2 Loosely, any centre fire rifle with a calibre less than .25 or any shotgun with a gauge less than 16.

Small of the stock
On a shoulder arm, the portion of the stock between the receiver and the comb, around which the shooting hand is placed.

Smokeless powder see Powder

Smoothbore
A rifle with an unrifled bore, such as musket, blunderbuss etc. Also sometimes used to describe a shotgun.

Snaphance, Snaphaunce, Snaphaan
An early flintlock invented in the Spanish Netherlands (Holland) simultaneously with the miquelet in Spain. The action is similar to later flintlocks except that the pan cover is manually operated. Dating from the 16th century the system may derive its name from a Dutch word meaning "chicken thief". The inventors employed in this occupation could not afford wheel locks and would have been betrayed by the lighted match of a matchlock. A similar requirement for an inexpensive, fire-less system led to the miquelet in Spain.

Solid frame
1 A rifle assembly that does not allow an easy separation of the barrel and the action.
2 On a revolver, an unhinged frame. Loosely a revolver in which cartridges must be ejected singly, or in which an axis pin must be withdrawn before the cylinder can be removed from the frame.

Spade bayonet
A broad bladed bayonet which may be used for digging.

Spanner
Of a wheel lock, a small wrench used to wind the action spring. Frequently the spanner was combined with a priming box.

Spent ball
A projectile which, having lost practically all of its velocity, lacks sufficient force to penetrate or injure seriously.

Split bridge see Receiver bridge

Stab crimp see Crimp

Stacking swivel
Of a rifle, a device attached to the barrel band to permit several weapons to be affixed to each other to form a stack. The buttstocks of such a stack rest on the ground and the barrels and actions are kept clear of the dirt. The swivel takes the form of an open metal loop on the underside of the barrel near the muzzle.

Standing breech
1 The rear wall of the receiver of a firearm, in which the receiver has not been cut away at its rear below the line of the gun bore.
2 Of a hinged breech weapon, the rearward portion of the frame against which the heads of chambered cartridges rest when the gun is locked.
3 of a revolver or single shot pistol, that section of the frame supporting the head of the cartridge in the cylinder or chamber.

Star gauge
A precision instrument used to determine generally at one inch intervals, the exact measurements of a weapons bore throughout its length.

Steel jacketed bullet see Bullet

Stock
The wooden part of a shoulder arm, attached to the receiver, by means of which the weapon is held, aimed and fired. Sometimes the stock may be made of metal, plastic or other rigid material. The quality and design of stock is of great importance in increasing the weapons accuracy.

Stone shot
Stone projectiles fired from guns in the 15th century and earlier.

Stop butt
A parapet, either natural or artificial, constructed to stop bullets behind targets on a firing range.

Straight pull action see Action, straight pull

Striker
A rod like firing pin moving within the bolt or breechblock and actuated by its own spring when released by the trigger. The striker moves straight forward in line with the firing pin, which may or may not be part of the rod.

Stripping
1 Failure of a bulletís jacket to take the rifling.
2 Of a magazine weapon, loading the magazine by pressing cartridges from a charger into the weapon.

Stud
In mechanics, any projection designed to make contact with another part to hold the latter in a desired position.

Subcalibre tube see Adapter

Submachine gun
A firearm lighter than an automatic rifle and firing pistol ammunition on automatic principles.