Uses a .512" bullet. noFAC.ca in Red Deer, AB sells the brass. Cheap it ain't though. $80 per 20.
Stole this from his site.
"carefully load .520 soft round ball on top of almost full cases of 2F rifle or 3F pistol H777 for slight powder compression then lube with lee bullet lube , air dry a day or 2. Don't worry about any lead slivers that shave off. If still hanging , peel shaving of by hand or trim/smooth with blade, have done this with .457 round ball in Webley .755 length .455 dia. cases behind 11 to 18 cc's of 3F H777 with large rifle primers by mistake. Pistol primers should give similar results. All fired fine with less residue than any modern powder I've used, all flew straight and true with little recoil."