I've known a few guys that had boltguns and SS's in 45-70 that would get the advertised velocities and then some. They were red-lining their guns to do so while I was only coasting along with my 375 and 458 at the time. The secret is and was, with these guns, to seat them out further than normal COL to increase powder capacity. While I was getting sub-moa groups, these guys were into the 2"-4" category with their very hot loads.