Is it true that the M4 assault rifle has no recoil?
This is a firearm. It works by burning powder in a confined space, with the pressure of the gases driving the bullet down the barrel. Since something moves in one direction, something else moves in the opposite direction. The bullet goes one way, the gun and everything attached to it including the shooter moves in the other direction. For every action there is an equal and opposite reaction. In this case a 55 grain bullet exits the muzzle at 2500 feet per second. If the gun weighs 5 pounds, it weight in grains is 7000*5 or 35000 grains. The gun moves backwards at a rate of 2500/35000 feet per second which equals 0.07 feet per second. There is not a great deal of recoil, but if you are firing the gun full auto it will result in that 0.07 FPS impulse times the number of cartridges per second. At 600 rounds per minute, there are 10 round per second for a sustained effective thrust of 0.7 FPS.
