Online sources for loading data can be found in the FAQ and Help, there are several powder mfr links in there, they all show smokeless data. Blackpowder loads are basically a case full of powder then compressed with a wad tween bullet and powder. There's a link to Junior Doughty's web site on the blackpowder Handi in the FAQ also. The Hodgdon Annual at Walmart for $7 has lots of load data for the .45-70 in all 3 loading levels. If you want to buy a good manual, the Lyman 48th is a good one to start with. There's also the caliber specific Loadbook that has data from every bullet and powder mfr available, all in one spiral bound booklet for $7 from Midway or $8 at Sportsman's Warehouse.
Tim