An opening in the barrel or receiver of a firearm for several purposes: (1) to allow the vented gas to operate a mechanism, (2) to reduce recoil, (3) to provide an escape route for high-pressure gases should a case or primer rupture upon firing, reducing the amount of gas that might be directed back through the action into the shooter’s face. May also be known as a gas vent. Also refer to Gas Port in the Suppressor Terminology Section of the appendix.
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