This board needs a wake-up call.....so while I sit here in the cubicle farm waiting for the farking phone to ring, I'll jump on in.
I have Ruger #1 in 45-70, and it is SUPERBLY accurate with cast bullets. I recently scoped the rifle to give my aging eyes an assist, and HIJO LA--it made ragged 1.25" to 1.5" 5-shot holes in targets at 50 yards. That's not center-to-center, either. The two designs that did this are the Lee 405 grain plain-base and the RCBS 300 grain flatnose/gas-check.
A couple things about the recent Ruger #1's--they have a "Government ballseat" which is VERY short and abrupt. This limits your bullet selection a bit, because longer sloping nose profiles will require deeper seating. The other thing about Ruger #1's is that they are LIGHT--mine weighs about 7 pounds minus scope and rings. If you load some of the full-potential charges with 400 grain bullets at 1900 FPS, the recoil will be memorable. Black powder-intensity loads (405's at 1300 FPS+/-) are all-day loads, though--very pleasant to fire, and will upend any deer every bred in North America.