I just started loading .45 Colt for my conversion cylinders, I did a lot of research before I bought any gear or even the cylinders to make sure it was feasible with my limited resources. No one carries real BP locally, I've been having to use Goex Pinnacle FFFg for my pistols, Shockey's Gold FF for my rifles, and 777 in both granulations for both. I ordered 10 lbs of mixed grades from Powder Inc. (
http://www.powderinc.com/index.html) last week. It's the least expensive for me. Jack's Powder Keg is another good supplier, if you can afford to buy powder 25 lb's at a time for $250.(
http://www.jackspowderkeg.com/) They both carry Goex and other brands. I bought 5 lbs of KIK FFF for a tad over $10 a lb, 4 lbs lbs of Goex FF and 1 lb of Goex Cowboy for about $13 a lb including shipping and hazmat.
Last week, I loaded one round with a Lee Loader and ten rounds of .45 Colt using my Lee carbide pistol dies and a Lee Hand Press. I was using once fired brass that had been shot through my Ruger Blackhawk years ago. I had some Large pistol Magnum primers and some .452" 255 LNWC Speer bullets left over from back then. I used 30 grains of Goex Pinnacle FFFg measured through my flask.
The Lee Loader doesn't size them through the whole length and it doesn't crimp the case. The round got stuck halfway in the chamber, I had to use a dowel to knock it out. The same thing happened to the rounds I used with the press. I pulled the bullets and dumped the powder back into my flask and took the decapper pin out so I could resize the cases properly without setting off the primers. Of course I pointed it at a safe direction, without the decapper pin and retention screw, it would be like shooting caps off if it went off. I tweaked the decapper pin so it would resize the case the full length as it decapped.
I also had to tweak the bullet seater to get a good crimp. After shooting 4 rounds in my Pietta Remington, the 5th bullet unseated itself and jammed the cylinder. I was able to squeeze it back in place. The Lee Loader doesn't crimp that round, so I assumed it didn't need it. It does.
I loaded up 35 more rounds the other night. I adjusted the bullet seater so it gave a good crimp. With 30 grains of Goex Pinnacle (which should be the same as 30 grains of BP) there was less than a quarter inch of space to the case mouth. The shoulder of the bullet easily compressed the powder so there wasn't any airspace to give problems. I didn't flare the casings on the second batch, but I should have, just a little.
I ordered a Lee LNWC .452" 200 grain bullet mold and I plan on casting up some bullets tonight so I can load some more.