Firearms Glossary
Comprehensive dictionary of firearms terminology with 18 terms.
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A
Action
The mechanism that loads, fires, and ejects cartridges.
Automatic Full-Auto
Continues firing as long as the trigger is held and ammunition remains. Heavily regulated (NFA).
B
Blowback
Operating system where expanding gases push the bolt/slide rearward.
Bolt Action
Manually operated action where the shooter cycles the bolt to chamber rounds.
Break Action
Action where the barrel(s) pivot away from the receiver for loading.
D
DA/SA Double Action/Single Action
First shot is double action, subsequent shots are single action.
DAO Double Action Only
Every trigger pull is double action. Common in some defensive pistols.
DI Direct Impingement
Gas system where gas is routed directly to the bolt carrier.
Double Action DA
Trigger both cocks and releases the hammer/striker in one pull.
G
Gas Operated
System using gas tapped from the barrel to cycle the action.
L
Lever Action
Action cycled by a lever, typically located around the trigger guard.
P
Piston Gas Piston
Gas system using a piston to drive the bolt carrier.
Pump Action
Action cycled by sliding a forend back and forth. Common in shotguns.
R
Revolver
Handgun with a rotating cylinder containing multiple chambers.
S
SAO Single Action Only
Requires manual cocking before each shot (e.g., 1911).
Semi-Automatic Semi-Auto
Fires one round per trigger pull, automatically chambering the next round.
Single Action SA
Trigger only releases the hammer/striker. Must be manually cocked first.
Striker-Fired
Action using a spring-loaded striker instead of a hammer.