As usual, begin with start loads and work up, the 45-70 doesn't show pressure signs like a bottleneck high pressure round, the signs are more subtle. In a Handi, the first sign is hard to press the barrel release to get the barrel open. The next is usually stuck brass with a bottleneck case, but the straight case 45-70 may not do that, then you're measuring case dimensions before and after full length resizing checking for too much case growth. Of course these tips are just if you want to push the high level 2 and into level 3 loads, which aren't for the recoil sensitive. :eek:
Good shooting to you.
Tim