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 we utilize in this load is very tough and gives only a small to moderately sized mushroom (about .60 cal) and because of the smallish mushroom, it penetrates very deep - about 4 feet in muscles and bone and as such is a great bullet for use on dangerous game and on smaller game too as it does expand some. This load is the most versatile of our 45-70 loads.