![Flickr - The U](https://upload.wikimedia.org/wikipedia/commons/4/49/Flickr_-_The_U.S._Army_-_www.Army.mil_%28350%29.jpg)
A muzzle brake or recoil compensator is a device connected to, or a feature integral to the construction of, the
muzzle or
barrel
A barrel or cask is a hollow cylindrical container with a bulging center, longer than it is wide. They are traditionally made of wooden staves and bound by wooden or metal hoops. The word vat is often used for large containers for liquids, ...
of a
firearm
A firearm is any type of gun designed to be readily carried and used by an individual. The term is legally defined further in different countries (see Legal definitions).
The first firearms originated in 10th-century China, when bamboo tubes ...
or
cannon
A cannon is a large- caliber gun classified as a type of artillery, which usually launches a projectile using explosive chemical propellant. Gunpowder ("black powder") was the primary propellant before the invention of smokeless powder ...
that is intended to redirect a portion of propellant gases to counter
recoil
Recoil (often called knockback, kickback or simply kick) is the rearward thrust generated when a gun is being discharged. In technical terms, the recoil is a result of conservation of momentum, as according to Newton's third law the force requ ...
and unwanted
muzzle rise
Muzzle rise, muzzle flip or muzzle climb refers to the tendency of a firearm's or airgun's muzzle (front end of the barrel) to rise up after firing. It more specifically refers to the seemingly unpredictable "jump" of the firearm's muzzle, cause ...
. Barrels with an integral muzzle brake are often said to be ported.
The concept of a muzzle brake was first introduced for artillery. It was a common feature on many
anti-tank gun
An anti-tank gun is a form of artillery designed to destroy tanks and other armored fighting vehicles, normally from a static defensive position. The development of specialized anti-tank munitions and anti-tank guns was prompted by the appearance ...
s, especially those mounted on
tank
A tank is an armoured fighting vehicle intended as a primary offensive weapon in front-line ground combat. Tank designs are a balance of heavy firepower, strong armour, and good battlefield mobility provided by tracks and a powerful engin ...
s, in order to reduce the area needed to take up the strokes of recoil and kickback. They have been used in various forms for rifles and pistols to help control recoil and the rising of the barrel that normally occurs after firing. They are used on pistols for
practical pistol competitions, and are usually called compensators in this context.
[STI article](_blank)
on Limcat Undergas Bypass Turbo System recoil compensator
Rationale
![MuzzleRise](https://upload.wikimedia.org/wikipedia/commons/e/eb/MuzzleRise.png)
The interchangeable terms
muzzle rise
Muzzle rise, muzzle flip or muzzle climb refers to the tendency of a firearm's or airgun's muzzle (front end of the barrel) to rise up after firing. It more specifically refers to the seemingly unpredictable "jump" of the firearm's muzzle, cause ...
, muzzle flip, or muzzle climb refer to the tendency of a handheld firearm's front end (the muzzle end of the barrel) to rise after firing. Firearms with less height from the grip line to the barrel centerline tend to experience less muzzle rise.
The muzzle rises primarily because, for most firearms, the centerline of the barrel is above the center of contact between the shooter and the firearm's grip and stock. The
reactive force As described by the third of Newton's laws of motion of classical mechanics, all forces occur in pairs such that if one object exerts a force on another object, then the second object exerts an equal and opposite reaction force on the first. The th ...
s from the fired bullet and propellant gases exiting the muzzle act directly down the centerline of the barrel.
If that line of force is above the center of the contact points, this creates a
moment
Moment or Moments may refer to:
* Present time
Music
* The Moments, American R&B vocal group Albums
* ''Moment'' (Dark Tranquillity album), 2020
* ''Moment'' (Speed album), 1998
* ''Moments'' (Darude album)
* ''Moments'' (Christine Guldbrand ...
or
torque
In physics and mechanics, torque is the rotational equivalent of linear force. It is also referred to as the moment of force (also abbreviated to moment). It represents the capability of a force to produce change in the rotational motion of th ...
(rotational force) that causes the firearm to rotate and the muzzle to rise. The
M1946 Sieg automatic rifle
The Sieg automatic rifle was a bullpup automatic rifle designed by Chief Gunner's Mate James E. Sieg of the US Coast Guard. The weapon was chambered in the .30-06 round, fed from 20 round magazines and capable of firing around 650–700 RPM on f ...
had an unusual muzzle brake that made the rifle climb downward, but enabled the user to fire it with one hand in full automatic.
Design and construction
![M47 main gun muzzle brake](https://upload.wikimedia.org/wikipedia/commons/d/d5/M47_main_gun_muzzle_brake.jpg)
Muzzle brakes are simple in concept, such as the one employed on the
90 mm M3 gun
9 (nine) is the natural number following and preceding .
Evolution of the Arabic digit
In the beginning, various Indians wrote a digit 9 similar in shape to the modern closing question mark without the bottom dot. The Kshatrapa, Andhra and ...
used on the
M47 Patton tank
The M47 Patton was an American main battle tank, a development of the M46 Patton mounting an updated turret, and was in turn further developed as the M48 Patton. It was the second American tank to be named after General George S. Patton, comman ...
. This consists of a small length of tubing (mounted at right angles) at the end of the barrel. Brakes most often utilize slots, vents, holes, baffles, and similar devices. The strategy of a muzzle brake is to ''redirect and control the burst of combustion gases'' following the departure of a projectile.
All muzzle brake designs share a basic principle: to partially divert combustion gases from the muzzle end of the bore at a (generally) perpendicular angle to the long axis of the barrel. The
momentum
In Newtonian mechanics, momentum (more specifically linear momentum or translational momentum) is the product of the mass and velocity of an object. It is a vector quantity, possessing a magnitude and a direction. If is an object's mass an ...
of the diverted gases thus does not add to the recoil. The angle toward which the gases are directed will fundamentally affect how the brake behaves. If gases are directed upward, they will exert a downward force and counteract
muzzle rise
Muzzle rise, muzzle flip or muzzle climb refers to the tendency of a firearm's or airgun's muzzle (front end of the barrel) to rise up after firing. It more specifically refers to the seemingly unpredictable "jump" of the firearm's muzzle, cause ...
. Any device that is attached to the end of the muzzle will also add mass, increasing its inertia and moving its center of mass forward; the former will reduce recoil and the latter will reduce muzzle rise.
![AKM muzzle brake](https://upload.wikimedia.org/wikipedia/commons/7/71/AKM_muzzle_brake.jpg)
Construction of a muzzle brake or compensator can be as simple as a diagonal cut at the muzzle end of the barrel to direct some of the escaping gas upward. On the
AKM
The AKM () is an assault rifle designed by Soviet small arms designer Mikhail Kalashnikov in 1959. It is the most ubiquitous rifle of the Kalashnikov rifles. It was developed as a replacement to the AK-47 introduced a decade prior.
Introduced ...
assault rifle, the brake also angles slightly to the right to counteract the sideways movement of the rifle under recoil.
Another simple method is porting, where holes or slots are machined into the barrel near the muzzle to allow the gas to escape.
More advanced designs use baffles and expansion chambers to slow escaping gases. This is the basic principle behind a linear compensator. Ports are often added to the expansion chambers, producing the long, multi-chambered recoil compensators often seen on
IPSC raceguns.
Venting direction
![Heizer-DoubleTap](https://upload.wikimedia.org/wikipedia/commons/a/ac/Heizer-DoubleTap.jpg)
Most linear compensators redirect the gases forward. Since that is where the
bullet
A bullet is a kinetic projectile, a component of firearm ammunition that is shot from a gun barrel. Bullets are made of a variety of materials, such as copper, lead, steel, polymer, rubber and even wax. Bullets are made in various shapes and co ...
is going, they typically work by allowing the gases to expand into the compensator, which surrounds the muzzle but only has holes facing forward; like any device which allows the gases to expand before leaving the firearm, they are effectively a type of
muzzle shroud
A muzzle shroud, linear compensator, blast shield, forward blast diverter or concussion reduction device (CRD) is a sleeve (either circular or otherwise) that attaches to and extends beyond the muzzle of a firearm in order to redirect some of t ...
. They reduce muzzle rise similarly to the mechanism by which a sideways brake does: since all the gas is escaping in the same direction, any muzzle rise would need to alter the velocity of the gas, which costs kinetic energy. When the brake redirects the gases directly backward, instead, the effect is similar to the
reverse thrust
Thrust reversal, also called reverse thrust, is the temporary diversion of an aircraft engine's thrust for it to act against the forward travel of the aircraft, providing deceleration. Thrust reverser systems are featured on many jet aircraft to ...
system on an aircraft jet engine: any blast energy coming back at the shooter is pushing "against" the recoil, effectively reducing the actual amount of recoil on the shooter. Of course, this also means the gases are directed toward the shooter.
When the gases are primarily directed upward, the braking is referred to as ''porting''. Porting typically involves precision-drilled ports or holes in the forward top part of the
barrel
A barrel or cask is a hollow cylindrical container with a bulging center, longer than it is wide. They are traditionally made of wooden staves and bound by wooden or metal hoops. The word vat is often used for large containers for liquids, ...
and
slide
Slide or Slides may refer to:
Places
* Slide, California, former name of Fortuna, California
Arts, entertainment, and media Music Albums
* ''Slide'' (Lisa Germano album), 1998
* ''Slide'' (George Clanton album), 2018
*''Slide'', by Patrick Glees ...
on
pistol
A pistol is a handgun, more specifically one with the chamber integral to its gun barrel, though in common usage the two terms are often used interchangeably. The English word was introduced in , when early handguns were produced in Europe, an ...
s. 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. The concept is an application of
Newton's third law
Newton's laws of motion are three basic laws of classical mechanics that describe the relationship between the motion of an object and the forces acting on it. These laws can be paraphrased as follows:
# A body remains at rest, or in motion ...
; the exhaust directed upward causes a reciprocal force downward. This is why firearms are never ported on the bottom of the barrel, as that would exacerbate muzzle rise, rather than mitigate it. Porting has the undesired consequences of shortening the effective barrel length and reducing muzzle velocity, while a muzzle brake is an extension added to the barrel and does not reduce muzzle velocity. Porting has the advantage for faster follow-up shots, especially for
3-round burst operation.
Effectiveness
Though there are numerous ways to measure the energy of a recoil
impulse
Impulse or Impulsive may refer to:
Science
* Impulse (physics), in mechanics, the change of momentum of an object; the integral of a force with respect to time
* Impulse noise (disambiguation)
* Specific impulse, the change in momentum per uni ...
, in general, a 10% to 50% reduction can be measured. Some muzzle brake manufacturers claim greater recoil reduction percentages. Muzzle brakes need sufficient propellant gas volume and high gas pressure at the muzzle of the firearm to achieve well-measured recoil reduction percentages. This means cartridges with a small bore area to case volume ratio (
overbore Overbore cartridges are those with a relatively large case volume or case capacity, coupled with a relatively small diameter bullet.
The case volume or case capacity and barrel bore area can be mathematically related to obtain a case volume to bore ...
cartridges) combined with a high operating pressure benefit more from recoil reduction with muzzle brakes than smaller standard cartridges.
Besides reducing felt recoil, one of the primary advantages of a muzzle brake is the reduction of muzzle rise. This lets a shooter realign a weapon's sights more quickly. This is relevant for fully automatic weapons. Muzzle rise can theoretically be eliminated by an efficient design. Because the rifle moves rearward less, the shooter has little to compensate for. Muzzle brakes benefit rapid-fire, fully automatic fire, and large-bore hunting rifles. They are also common on small-bore
vermin
Vermin (colloquially varmint(s) or varmit(s)) are pests or nuisance animals that spread diseases or destroy crops or livestock. Since the term is defined in relation to human activities, which species are included vary by region and enterpr ...
rifles, where reducing the muzzle rise lets the shooter see the bullet impact through a
telescopic sight
A telescopic sight, commonly called a scope informally, is an optical sighting device based on a refracting telescope. It is equipped with some form of a referencing pattern – known as a ''reticle'' – mounted in a focally appropriate po ...
. A reduction in recoil also reduces the chance of undesired (painful) contacts between the shooter's head and the ocular of a telescopic sight or other aiming components that must be positioned near the shooter's eye (often referred to as "scope eye"). 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.
Disadvantages
![120704-A-IX566-193 (7557291576)](https://upload.wikimedia.org/wikipedia/commons/f/f2/120704-A-IX566-193_%287557291576%29.jpg)
There are a number of potential downsides to brakes and compensators.
The shooter, gun crew, or close bystanders may perceive an increase in sound pressure level as well as an increase in muzzle blast and
lead exposure
Lead poisoning, also known as plumbism and saturnism, is a type of metal poisoning caused by lead in the body. The brain is the most sensitive. Symptoms may include abdominal pain, constipation, headaches, irritability, memory problems, infe ...
. This occurs because the sound, flash, pressure waves, and lead loaded smoke plume normally projected away from the shooter are now partially redirected outward to the side or sometimes at partially backward angles toward the shooter or gun crew. Standard eye and ear protection, important for all shooters, may not be adequate to avoid
hearing damage
Hearing loss is a partial or total inability to hear. Hearing loss may be present at birth or acquired at any time afterwards. Hearing loss may occur in one or both ears. In children, hearing problems can affect the ability to acquire spoken l ...
with the muzzle blast partially vectored back toward the gun crew or spotters by arrowhead shaped reactive muzzle brakes found on
sniper team
A sniper is a military/paramilitary marksman who engages targets from positions of concealment or at distances exceeding the target's detection capabilities. Snipers generally have specialized training and are equipped with high-precision r ...
s firing
anti-materiel rifle
An anti-materiel rifle (AMR) is a rifle designed for use against military equipment, structures, and other hardware (materiel). Anti-materiel rifles are chambered in significantly larger calibers than conventional rifles and are employed to elimin ...
s like the
Barrett M82
The Barrett M82 (standardized by the U.S. military as the M107) is a recoil-operated, semi-automatic anti-materiel rifle developed by the American company Barrett Firearms Manufacturing.
Also called the Light Fifty (due to its chambering of ...
.
Measurements indicate that on a rifle, a muzzle brake adds 5 to 10 dB to the normal noise level perceived by the shooter, increasing total noise levels up to 160 dB(A) ± 3 dB. Painful discomfort occurs at approximately 120 to 125 dB(A), with some references claiming 133 dB(A) for the threshold of pain.
Brakes and compensators also add length, diameter, and mass to the muzzle end of a firearm, where it most influences its handling and may interfere with accuracy as muzzle rise will occur when the brake is removed and shooting without the brake can throw off the strike of the round.
Another problem can occur when
sabot
Sabot may refer to:
* Sabot (firearms), disposable supportive device used in gunpowder ammunitions to fit/patch around a sub-caliber projectile
* Sabot (shoe), a type of wooden shoe
People
* Dick Sabot (1944–2005), American economist and busi ...
ed ammunition is used as the sabot tends to break up inside the brake. The problem is particularly pronounced when
armour-piercing fin-stabilized discarding-sabot (APFSDS), a type of
long-rod penetrator (LRP) (or kinetic energy penetrator), are used.
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.
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.
Linear compensators and
suppressor
A silencer, also known as a sound suppressor, suppressor, or sound moderator, is a muzzle device that reduces the acoustic intensity
Sound intensity, also known as acoustic intensity, is defined as the power carried by sound waves per unit ...
s do not have the disadvantages of a redirected muzzle blast; they actually reduce the blast by venting high pressure gas forward at reduced velocity.
The redirection of larger amounts of escaping high-pressure gas can cause discomfort caused by blast-induced
sinus cavity
Paranasal sinuses are a group of four paired air-filled spaces that surround the nasal cavity. The maxillary sinuses are located under the eyes; the frontal sinuses are above the eyes; the ethmoidal sinuses are between the eyes and the sphenoid ...
concussion. Such discomfort can especially become a problem for
anti-materiel rifle
An anti-materiel rifle (AMR) is a rifle designed for use against military equipment, structures, and other hardware (materiel). Anti-materiel rifles are chambered in significantly larger calibers than conventional rifles and are employed to elimin ...
shooters due to the bigger than normal cartridges with accompanying large case capacities and propellant volumes these rifles use and can be a reason for promoting accelerated shooter fatigue and flinching. Furthermore, the redirected blast may direct pressure waves toward the eye, potentially leading to
retinal detachment
Retinal detachment is a disorder of the eye in which the retina peels away from its underlying layer of support tissue. Initial detachment may be localized, but without rapid treatment the entire retina may detach, leading to vision loss and blin ...
when repeated shooting is performed with anti-materiel and large caliber weapons.
Examples
File:Flickr - ~Steve Z~ - S^W 500 Magnum (1).jpg, The S&W Model 500 revolver features a muzzle brake
File:Muzzle break 30mm mauser machine canon.jpg, The muzzle brake of a 30mm Mauser autocannon
An autocannon, automatic cannon or machine cannon is a fully automatic gun that is capable of rapid-firing large-caliber ( or more) armour-piercing, explosive or incendiary shells, as opposed to the smaller-caliber kinetic projectiles (bull ...
File:Air force female sniper.jpg, The arrowhead-shaped muzzle brake on the Barrett M82 anti-materiel/sniper rifle
File:PGM-Hecate-seul-img 1008.jpg, The prominent muzzle brake of the PGM Hécate II The Hécate II is the standard heavy sniper rifle and anti-materiel rifle of the French Army, sometimes known as the FR-12.7 (french: Fusil à Répétition de calibre 12.7 mm or "12.7 mm calibre repeating rifle"). It is manufactured by PGM Pré ...
File:Muzzle of a .375H&H Rifle.JPG, Integral muzzle brake or porting on a Blaser R93
The Blaser R93 is a straight-pull action precision rifle offered in a multitude of calibers and barrel lengths manufactured by the German firearms manufacturer Blaser. Designed by Blasers' designer Mr. Meinhard Zeh in 1993, it had a number ...
hunting rifle.
US legislation and regulation
The State of California outlaws
flash suppressor
A flash suppressor, also known as a flash guard, flash eliminator, flash hider, or flash cone, is a muzzle device attached to the muzzle of a rifle that reduces its visible signature while firing by cooling or dispersing the burning gases that ...
s on semiautomatic rifles with detachable magazines, but allows muzzle brakes to be used instead.
The
Bureau of Alcohol, Tobacco, Firearms, and Explosives
The Bureau of Alcohol, Tobacco, Firearms and Explosives (BATFE), commonly referred to as the ATF, is a domestic law enforcement agency within the United States Department of Justice. Its responsibilities include the investigation and preven ...
(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
A silencer, also known as a sound suppressor, suppressor, or sound moderator, is a muzzle device that reduces the acoustic intensity
Sound intensity, also known as acoustic intensity, is defined as the power carried by sound waves per unit ...
and claimed by SIG to be a muzzle brake, constituted a silencer and rendered the MPX-C a Title II
NFA weapon.
SIG Sauer
Several brother companies that design and manufacture firearms use the brand name SIG Sauer . The original company, ''Schweizerische Waggon-Fabrik'' (SWF), later ''Schweizerische Industrie-Gesellschaft'' (SIG), went through several selloffs, ...
, the rifle's maker, sued the ATF in 2014 to have the designation overturned. In September 2015, Federal Judge Paul Barbadora upheld the ATF's ruling; despite SIG successfully establishing that the muzzle device did not suppress the weapon's sound, the ATF successfully established that it was ''intended'' to suppress the sound, which was legally sufficient.
''Judge favors ATF in Sig lawsuit: It’s a silencer''
, Guns.com, 25 September 2015
See also
* Flash suppressor
A flash suppressor, also known as a flash guard, flash eliminator, flash hider, or flash cone, is a muzzle device attached to the muzzle of a rifle that reduces its visible signature while firing by cooling or dispersing the burning gases that ...
* Muzzle booster
A muzzle booster or recoil booster is a device fixed to the muzzle of a firearm, intended to harness the energy of the escaping propellant to augment the force of recoil on portions of the firearm. In spite of its name, a muzzle booster does not ...
* Muzzle shroud
A muzzle shroud, linear compensator, blast shield, forward blast diverter or concussion reduction device (CRD) is a sleeve (either circular or otherwise) that attaches to and extends beyond the muzzle of a firearm in order to redirect some of t ...
* Silencer (firearms)
A silencer, also known as a sound suppressor, suppressor, or sound moderator, is a Gun barrel#Muzzle, muzzle device that reduces the Sound intensity, acoustic intensity of the muzzle report (sound of a gunshot) and muzzle rise when a gun (fir ...
References
External links
{{Commons category, Muzzle brakes
High speed photography on muzzle brakes
article on muzzle brakes
Adventures with muzzle brakes
Firearm muzzle devices
Artillery components
Tank subassembly