Muzzle brake
Appearance
A muzzle brake is a device that is affixed to the muzzle of a firearm, and which redirects propellant gasses to either counter the recoil of the gun, or to prevent the muzzle from climbing during rapid fire. They are very useful for combat and timed competition shooting, and are commonly found on rifles firing very large catridges (often big-game rifles).
The major disadvantage to using a muzzle brake is the fact that they necessarily increase the noise level of the report dramatically; generally, the more effective the muzzle brake is, the louder it will be.