Muzzle brake

A muzzle brake or compensator is a device that is affixed to the muzzle of a firearm, and which redirects propellant gases 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 cartridges (often big-game rifles), as well as some artillery and tank guns. They are also commonly used on pistols for practical pistol competitions, and are usually called compensators in this context.

Muzzle brakes are simple in concept. One of the simplest designs can be found on U.S. 90 mm tank guns, which consisted of a small length of tubing mounted at right angles to the end of the barrel. As the shell left the barrel the gases would rush around it, hitting the inside "front" of this tube, pushing it, and thus the gun as a whole, forward.

Brakes more typically consist of a small length of tubing "fit over" the end of the barrel, pointing in the same direction. Slits or holes are cut into the tube, angled toward the rear of the gun. When a round is fired there is a brief period in which the bullet is at the end of the brake, but not yet exited. During this time the gases pushing the round escape through the holes to the rear, countering the recoil.

There are advantages and disadvantages to muzzle brakes on firearms. Despite manufacturers claims of recoil reduction of 50% and more, that is really physically impossible. What is really happening is that because the muzzle break tends to reduce lateral movement as well as recoil to the shooter it may well feel like half the recoil has been mitigated. The other two primary advantages to the muzzle brake are that because they minimize lateral movement of the barrel the gun does not move far off target facilitating quick reacquisition of the target for additional shots. This is a big advantage on fully automatic weapons. The other thing that well designed muzzle brake does is increase accuracy. The gasses rushing by the round just as it leaves the barrel can cause it to be deflected; by diverting the gasses at exactly this point this deflection can be reduced. Certain types of muzzle brakes slightly stabilize the bullet at this juncture and noticeably decrease shot to shot deviation.

The disadvantage to a muzzle brake is that it is directing propellant gasses at a 90-degree angle to the line of fire, the consequence of this is that it is effectively directing the weapons report sideways as well. Weapons with muzzle brakes sound significantly louder, particularly to anybody on either side of the weapon. Another disadvantage of the muzzle brake is that because they are diverting super hot propellant gasses at right angles to the bore of the weapon, the muzzle flash is significantly larger. Although this is not readily apparent in daylight, at night it is brilliantly apparent, which is a particular issue to the military. Some muzzle brakes are better than others in regard to muzzle flash but nobody has yet designed a muzzle brake that can minimize muzzle flash to the level of that achieved with modern military flash hiders of the Vortex design.

Muzzle brakes on both small arms and artillery pieces can also cause escaping gases to throw up dust clouds, obscuring visibility and making the firer easier to spot by the enemy. Troops often wet the ground in front of antitank guns in defensive emplacements, to prevent this.