Recoil
USMC Machine Gunner shooting the M60 GPMG without mount support.
The backwards momentum and kick that is applied to a weapon when in reaction to a bullet or projectile being fired.
Gameplay Details
Each projectile weapon has different recoil depending on its weight, caliber, and rate of fire. Crouching, going prone, or supporting the weapon on a surface can mitigate this recoil somewhat. Machine guns must have their bipods extended to get the full benefit of recoil reduction.