The 45-70 is, unfortunately, a slightly tapered round. You will end up lubing them, I use Imperial sizing wax. Since all my 45-70s are single shot, I only full length size when using new brass. I just bell the cases slightly, insert the powder of choice and seat/crimp using a very light crimp. I use TrailBoss powder for a mild load and can still hit the gong at 500 yards with the 30" Pedersoli rolling block, on a good day. We have alot of wind east of the mountains in Oregon...that's my story and I'm sticking to it.
FM