Recoil is the rearward thrust generated when a gun discharges, caused by Newton’s third law of motion1. This physical force, commonly called knockback or kick, occurs when the forward momentum of the projectile and exhaust gases creates an equal but opposite reaction on the firearm1.
Basic Physics of Recoil
The force behind recoil stems from extreme chamber pressures reaching hundreds of megapascals and accelerations thousands of times greater than gravity1. When a gun fires, the same pressure propelling the bullet forward pushes the gun backward. A 9mm Parabellum bullet weighing 8 grams traveling at 350 m/s will push a 0.8 kg pistol backward at 3.5 m/s1.
Managing Recoil Forces
Counter-Recoil Systems
Modern firearms use various mechanisms to control recoil. Hand-held weapons rely on the shooter’s body to absorb the force, while mounted guns employ springs and hydraulic systems similar to car shock absorbers1. These systems spread the recoil force over a longer time period, making it more manageable1.
Muzzle Devices
Muzzle brakes redirect propellant gases backward to create a counter-force1. Recoilless guns take this further by venting gases through a rear nozzle, though this reduces bullet velocity1.
Human Factors
The perception of recoil varies among shooters based on:
- Body size and strength
- Recoil padding usage
- Individual pain tolerance
- Firearm weight
- Presence of recoil buffering systems1
Mathematical Framework
The recoil force follows the conservation of momentum principle:pf+pp=0pf+pp=0Where:
- pfpf represents firearm momentum
- pppp represents projectile momentum1
Modern Applications
M16 rifles exemplify modern design by aligning the stock with the barrel to minimize rotational effects1. This straight-line configuration improves accuracy and shooter comfort compared to older designs like the Kentucky rifle with its angled stock.
https://en.wikipedia.org/wiki/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 required to accelerate something will evoke an equal but opposite reactional force, which means the forward momentum gained by the projectile and exhaust gases (ejectae) will be mathematically balanced out by an equal and opposite momentum exerted back upon the gun.
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