Just loaded 550 rounds of .45 Colt
I shot my .45 Colt Blackhawk 7.5" on Tuesday, cast and sized bullets last night, loaded today. I use 3 Lyman molds, 454190 250 gr.(round nose flat point, 2 small grease grooves, crimps on the ogive), 454424 250 gr.(swc with a huge meplat, looks like a manhole cover), and 452490 250 gr.(gas checked swc).
I load the 452490 gas checked between 1200 and 1300 fps. I use 21 gr of W296, 20 gr of Lil'Gun, or 22 gr of H4227. Any of these gives me about 10" to 12" groups bench rested at 100 yds, iron sights. No leading.
For the 454424 plain base I usually load it to between 1000 and 1100 with 7.5 gr Bullseye, 10 gr Unique, 13.5 gr Blue Dot, or 15 gr AA#7. I have also used Titegroup, 700X, HP 38, HS6 and PB in the recent past. I get some minimal leading just past the forcing cone with the fast powders, it stops with Unique and slower.
The 454190 leads with every combination I've tried. Some minimal, some awful. Shoots 10" groups with 13.5 gr Blue dot, 100 yds bench rested, and leads the lenght of the barrel, velocity is 1060 fps.
I cast and shoot wheel weights. No additives, alloying, heat treating nor nothing. I also use an Oheler 35P chrono. I've had it 3 years and should of had it 30.
Hope that helps.