I have a Navy Arms Rolling Block in 45-70 Gvt. Love the rifle. It is a dream to shoot, almost 14lbs of full octagon fun. It'll shoot one hole @ 100yds and a couple feet @1000, even with black powder handloads. It has a lot to do with that 34" bbl, 1 1/8" across the flats, the case hardened reciever is beautiful, bright colors. Only issue with it is that the breech end of the lands start with such a sharp edge that I get some lead buildup there with my own 500g hardcasts, but keep'em under about 1300fps and there is no fouling downbore.
Overall, it's one of the finest rifles I've ever been fortunate enough to experience. Anyone else have anything similar?