Bumpfire, or bump firing*, is a technique used with semi-automatic firearms to replicate full-automatic fire, using the recoil and weight of the firearm to engage the trigger. This technique can be used with any semi-automatic firearm by affixing the trigger with a stationary object and pulling the handguard forward to fire a round.

Bump fire stocks, an aftermarket product which replaces the pistol-grip furniture of a rifle to accommodate bump firing, have recently come under scrutiny with their involvement in the Las Vegas massacre, although previously available for many years in the US.

Bump fire is viewed by many enthusiasts as a novelty, ineffective for combat or self-defense due to the uncertainty of the technique and inaccuracy of sustained rates of fire.
Johnny: I want to learn how to bumpfire my Ar-15

Bill: I'm calling the FBI
by 🐺 February 24, 2018
Bumpfire is the method using the recoil of a firearm to simulate full auto fire.
Sometimes a rubber band is involved
by July 15, 2009
1) The practice of doing bumpfire or bumpfiring a semi-automatic rifle by needlessly, inefficiently and probably unsafely having a buddy stand behind you and pull the stock of your slinged rifle. 2) Any needless, inefficient and unsafe variation on standard shooting protocol usually thought up by two (almost always male) friends when they have more ammo than targets or good sense. See, Kentucky Windage.
Hey, why is that guy using himself as a bipod for his buddy's AR?
Hmm...That right there, son, is some serious Kentucky Bumpfire.
by Tin Hat Kippah December 21, 2020