My H&R 45-70 is very accurate with Hornady 325 gr. leverevolution, Remington corelokts, and plain blue box winchesters...great shooting gun.... have killed 3 deer with it - all dropped in their tracks. Mine shoots nearly touching holes in paper at 100 yds.... SMoffet reloads the 325 gr. Hornadys and has great results - will probably share his load info.....
The Hornady 325-gr FTX were good, but I switched to the Remington 300 JHP because I got a little better accuracy, and the Rems were significantly cheaper. Also had an FTX that performed kinda weird -- bullet went in the ribs and turned upward and ran through the backstrap, and the jacket came off -- although that was probably because it was moving out close to 2100 fps, and I shot the deer at 25 yards. My guess is the bullet probably wasn't designed for that kinda velocity.
Anyway my current load is...
CCI 200 large rifle primers
Rem 300-gr JHP
51 grains RL7
COAL = 2.585"
Light Lee factory crimp
Disclaimer: This load could blow up your rifle and/or you. Please reduce the load at least 10% and work up, watching for pressure signs. Don't even think about using this load in an old historic rifle. Also, you might want a scope with greater than 3" eye relief (ask me how I know ;-)