Our 45-70 ammunition is externally identical to SAAMI spec 45-70 ammo, but internally it generates FAR more power and pressure. So, our 45-70 ammo will fit into ANY 45-70 firearm but is not safe in every 45-70 firearm. The bullet utilized in this load will expand radically and will penetrate only about 18 to 24 inches in muscle and bone and was designed for use on animals weighing no more than 400 lb. At 2350 fps it is very fast and flat shooting.