Sonic Boom Exploding Rifle Targets 1 lb. 4 pk.The targets use a two part mixture that are easy to mix and easy to use, simply mix and shoot. Targets are made with high quality, non hazardous, non toxic and stable chemicals in a highly visible blaze orange jar. To ensure safety, shooters must be at least 50 yards from exploding target. To initiate explosion, rifle target must be struck with a center fire rifle projectile, weighting at least 40 grains and traveling at a minimum of 2200 fps, pistol