Recoil
This article is about backward momentum in firearms. For other uses, see recoil (disambiguation). |
An early naval cannon design, allowing the gun to roll backwards a small distance when firing |
The
recoil when firing a
gun is the backward
momentum of a gun, which is equal to the forward momentum of the
bullet or
shell, due to
conservation of momentum. It has to be absorbed by for example the
wrist, the
shoulder or the carriage.
For
handguns it has to be limited to avoid breaking one's wrist, see also
cartridge.
It should be noted that the impact to the target can be no greater than the impact of the recoil, due to the law of conservation of momentum. However, the smaller size of the bullet, compared to the gun-and-shooter system, allows significantly higher
energy to be imparted to the bullet than to the shooter. This is what gives guns their lethal effect. See
physics of firearms for a more detailed discussion.
Hollywood depictions of firearm victims being thrown through plate-glass windows are inaccurate, as were this to be the case, the shooter would also be thrown backwards with equal force. However, gunshot victims frequently do collapse when shot, but this is usually due to the effect of the energy of the bullet on their body systems, not the momentum of the bullet pushing them over. Of course this does not apply if the victim is hit by heavy weapons fire such as aircraft cannon, where the momentum effects can be enormous. The recoil from such a weapon is equally enormous, and requires it to be mounted on a
weapons platform.
A recoil system absorbs momentum, for example by the barrel moving backwards.
Cannons and such weapons without a recoil system roll several meters backwards when fired.
In a
soft-recoil system, a gun's barrel is moved forward prior to
shooting. As the barrel is forced backwards by the recoil force, the
energy is reduced by
friction, resulting in less of an overall "kick". One of the early guns to use this was the
French 65 mm mle.1906; however, this method did not receive much attention until the
1970s.
|
Recoilless designs allow larger and faster projectiles to be shoulder-launched |
Recoilless rifles and
rocket launchers exhaust gas to the rear, balancing the recoil. They are used as light
anti-tank weapons.
*
Recoil buffer
