Firearms Glossary
Comprehensive dictionary of firearms terminology with 28 terms.
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B
Barrel
The metal tube through which the bullet travels. Rifling imparts spin for stability.
BCG Bolt Carrier Group
The assembly in semi-auto rifles that chambers rounds, fires, extracts, and ejects casings.
Bore
The interior of the barrel through which the bullet passes.
Buttstock
The rear portion of the stock that contacts the shooter's shoulder.
C
Chamber
The portion of the barrel where the cartridge sits before firing.
Clip
A device that holds cartridges together for loading into a magazine. Often incorrectly used to mean magazine.
Compensator
Muzzle device that redirects gases upward to reduce muzzle rise.
F
Flash Hider
Device that disperses muzzle flash to reduce visibility to the shooter.
H
Hammer
A pivoting component that strikes the firing pin when released by the trigger.
Handguard
The portion of the firearm surrounding the barrel that protects the shooter's hand from heat.
K
KeyMod
A modular mounting system using keyhole-shaped slots.
L
Lower Receiver
On AR-style rifles, the serialized portion containing the trigger group and magazine well.
M
M-LOK
A modular accessory mounting system using slots and locking lugs.
Magazine
A detachable container holding ammunition that feeds into the firearm.
Muzzle
The end of the barrel where the bullet exits.
Muzzle Brake
Device attached to the muzzle that redirects gases to reduce felt recoil.
P
Pistol Grip
A grip that allows the hand to hold the firearm at an angle similar to holding a pistol.
R
Rail Picatinny Rail
A mounting platform with standardized slots for attaching accessories.
Receiver
The main body of a firearm that houses the operating parts. Legally considered the 'firearm.'
Rifling
Spiral grooves cut into the barrel bore that spin the bullet for accuracy and stability.
S
Safety
A mechanism that prevents the firearm from firing when engaged.
Stock
The part of a long gun that braces against the shoulder.
Striker
A spring-loaded firing pin that strikes the primer when released by the trigger.
Suppressor Silencer
Device that reduces the sound and flash of a firearm. NFA regulated item.
T
Trigger
The lever pulled by the finger to fire the weapon.
Trigger Pull
The amount of force required to release the striker or hammer.
Twist Rate
The rate of spin imparted by rifling, expressed as 1:X (one rotation per X inches).
U
Upper Receiver
On AR-style rifles, the portion containing the barrel, bolt carrier group, and charging handle.