Reloader7, h4198 and 3031 for full loads, but I too, use 5744 for my 45-70's,45-90 and 45-100. In my 45-70 pistol the RCBS 405 RNFPGC bullet shoots fantastic and it drops deer where they stand. I use 30-1 lead and the hole coming out is around the size of a golf ball. Dad uses the speer 400gr bullet in his marlin CB, that too drops deer very quickly. He also took a buffalo last yr with a 525gr RNFP bullet out of his shiloh, at 20-1, lead it was found just inside the hide on the off shoulder. Really you could get some 350gr bullets and go hunting, unless your hunting BIG animals there isnt much that will walk away from a 45-70. We use Fed210m's in just about all our loads one uses CCI BR2's.
In a single shot rifle you will NOT need a roll crimp, just use enough to keep the bullet from falling out. A taper crimp die works great, or you can just use you FL resize die to add crimp. If you choose to use cast lead, seat your bullets so they touch or just engrave the rifling. Felix lube has worked wonders with smokeless powder. Most Single shot rifles today use a 1-18 twist so your bullet selection is pretty much......whatever you want up to 540gr or so. If you dont cast, you can buy cast bullets, but they are generally pretty hard and are shipped with lube that is also very hard. If it were me (and its not) I would stay away from those and just use jacketed at that point.
IF you choose to go down the BP route I would suggest going to the Shiloh Forum's....there is more info there than you will want to ever know about BP and 45-70.
Regards,
BPCR Shooter