I cast the 50 and 54 caliber minnie. I tried them in a LOT of rifles. I paper patched them and anything else I could think of doing. Granted a man size target I could have hit with them. But the kind of hunting accuracy I demand.. never got it. Now I have seen the minnie shot out of an Enfield that did a real good job of shooting them. This was at a re-enactment camp. And the person shooting did a lot of it. He was hitting cinder blocks easy.. at 50 and 75 yards. Impressive results I might add with only 60 grains of powder. But an Enfield I believe was a .577 diameter bore and so is a 58 minnie so in that case it would be almost like a slip fit conical.