Firebird Targets are designed for use with most centerfire rifles, handguns, and shotguns using standard factory loaded ammunition. Higher velocity rounds generally provide the best target activation. Rimfire, low velocity ammo, airguns, pellet guns will activate the targets if the weapon is able to achieve the velocity of 850 fps at 50 feet. The targets are unlikely to function with BB guns, airsoft guns, and guns less than 850 fps. If the distance to the target increases, the velocity would also need to increase. See the Weapons video here