Abstract: An anti-recoil device can be mounted on the muzzle end of a firearm. The device includes a barrel extension, and provides a weight surrounding the barrel extension. Gas from the bore is diverted to move the weight forward, preferably at the speed of the bullet; then, the weight is abruptly stopped when the bullet leaves the muzzle. The forwardly directed force to stop the weight effectively counteracts the rearwardly direction force of the muzzle recoil. A washer of an elastomeric material can be used at the stop to prevent damage to metal parts, and to distribute the stopping over a short period of time.