Muzzle brake
It was a common feature on many anti-tank guns, especially those mounted on tanks, in order to reduce the area needed to take up the strokes of recoil and kickback.
[4] A US patent was issued for a "recoil obviator" in 1871 (there is no indication it was ever tested),[5] while an experimental British anti-tank rifle in 1918 featured a muzzle brake, but was not adopted.
The reactive forces from the fired bullet and propellant gases exiting the muzzle act directly down the centerline of the barrel.
Another simple method is porting, where holes or slots are machined into the barrel near the muzzle to allow the gas to escape.
Ports are often added to the expansion chambers, producing the long, multi-chambered recoil compensators often seen on IPSC raceguns.
These holes divert a portion of the gases expelled prior to the departure of the projectile in a direction that reduces the tendency of the firearm to rise.
[17] The concept is an application of Newton's third law; the exhaust directed upward causes a reciprocal force downward.
They are also common on small-bore vermin rifles, where reducing the muzzle rise lets the shooter see the bullet impact through a telescopic sight.
Another advantage of a muzzle brake is a reduction of recoil fatigue during extended practice sessions, enabling the shooter to consecutively fire more rounds accurately.
Further, flinch (involuntary pre-trigger-release anxiety behavior resulting in inaccurate aiming and shooting) caused by excessive recoil may be reduced or eliminated.
Standard eye and ear protection, important for all shooters, may not be adequate to avoid hearing damage with the muzzle blast partially vectored back toward the gun crew or spotters by arrowhead shaped reactive muzzle brakes found on sniper teams firing anti-materiel rifles like the Barrett M82.
[23] Since these APFSDS rounds are the most common armour-piercing ammunition currently, virtually no modern main battle tank guns have muzzle brakes.
A serious tactical disadvantage of muzzle brakes on both small arms and artillery is that, depending on their designs, they may cause escaping gases to throw up dust and debris clouds that impair visibility and reveal one's position, not to mention posing a hazard to individuals without eye protection.
[24] Troops often wet the ground in front of antitank guns in defensive emplacements to prevent this, and snipers are specially trained in techniques for suppressing or concealing the magnified effects of lateral muzzle blast when firing rifles with such brakes.
Furthermore, the redirected blast may direct pressure waves toward the eye, potentially leading to retinal detachment when repeated shooting is performed with anti-materiel and large caliber weapons.
[27] The State of California outlaws flash suppressors on semiautomatic rifles with detachable magazines, but allows muzzle brakes to be used instead.
[28] The Bureau of Alcohol, Tobacco, Firearms, and Explosives (ATF) made a regulatory determination in 2013 that the muzzle device of the SIG Sauer MPX Carbine, adapted from the baffle core of the integrally suppressed version's suppressor and claimed by SIG to be a muzzle brake, constituted a silencer and rendered the MPX-C a Title II NFA weapon.
