US Patent 8671818 Firearm discharge gas flow control

A firearm discharge gas flow control device can comprise a first gas chamber fluidly connectable to a muzzle end of a firearm to allow a projectile to pass through and to receive a first portion of a discharge gas generated by firing the projectile. The device can also comprise a second gas chamber fluidly isolated from the first gas chamber and fluidly connectable to the muzzle end of the firearm to receive a second portion of the discharge gas, the second gas chamber having a flow control barrier to modify a flow of the second portion of the discharge gas.