I've been loading GooseGestapo's 14.5 grains 2400 in a .357 under my Lee gas checked cast SWC for years, so when I got a .45 Colt to play with, I worked up my hot loads with it, first in a contender barrel, then the same load proved awesome in my Ruger Blackhawk I bought later.
I load 20 grains under a 300 grain Hornady XTP JHP. It's a fire breathin', butt stompin' load I'd NEVER try in a weaker gun than the Ruger or TC, so don't even THINK about it! I cannot remember where I got that load, but think it was out of a magazine article. It works, but it's pretty hot. I get no pressure signs like sticky cases or extruded primers or anything with it, though.
I've read of much hotter loads to be fired in the Freedom Arms revolvers only. I guess that's in case you can't find .454 brass or something, but I don't see the point in that. My load is .44 mag equivalent, but I don't shoot it all that much. It kinda HURTS to shoot it in that Contender.
The Blackhawk just rolls up in the hand with it, no problem.
I load a 255 grain Lee SWC that I mostly shoot. The 300 grain load is my serious outdoor load for hog hunting and I've carried it out west some where bears and cats roam. My 255 grain load is a hoot to shoot, load 8.3 grains of Unique under that Lee cast bullet and get honest to God 1" five shot groups off sandbags at 25 yards with it. It's pushing that big flat point at about 900 fps, be a pretty good anti-personel load I'd thing for self defense asside from a might too much penetration, but I don't worry about that out where I wear this hog leg. It's accurate enough to take a sitting jack rabbit out to 50 yards no problem. The Blackhawk is my favorite handgun in all my collection, though it's only suited for outdoor carry of course, but it's such a versatile firearm when handloaded. I think I'd like .41 mag for the same reasons and of course .44 mag ain't shabby, but I chose the .45 colt out of nostalgia if nothing else for this use and it's not disappointed me. It certainly carries more authority than my .357 mags. I get 1256 fps/1050 ft lbs out of my 7" contender barrel with the 300 grain load, something under 1200 fps in the Ruger (4 5/8" barrel).