A barrel vent is a port(s) in the barrel wall, commonly near the muzzle, through which gases formed during propellant burn escape prior to the projectile(s) exiting the barrel.
related:
- muzzle break
Footnotes / Sources:
“Glossary ⇒.” Sporting Arms and Ammunition Manufacturers’ Institute. Ed. SAAMI’s Technical Committee. Web. 15-18 Jan. 2011.