I don't think the brasser will stretch much with anything of a BP nature, even 777. BUT, I ain't gonna swear to that. The gun, though, just doesn't hold much powder. I have loaded a full charge behind a cast 60 grain conical in my brass framed ASM Remmy for chronographing and get 900 fps. Now, same gun loaded with a round ball (00 buck, actually) over a full charge of pyrodex only pushes about 700 fps. I've shot my brasser moderately, probably only about 500 rounds through it, the vast majority of that using pyrodex with round ball, some conical, but ball loads easier. It's still as tight as ever, nice little gun. I don't bother with downloading it, but I don't shoot a lot of 777 in it, either, just what I've done, a few cylinders full, testing. If I had to carry that gun, 777 load and conical is what I'd carry in it. It's sorta pathetic with Pyrodex.
Not a lot of help, just my two cents. BTW, I gave $62.50 for mine ordered from Gander Mountain on sale 20 years ago when they still had a mail order catalog. Guess the price of those things has gone up.
I just ordered it because I wanted another gun and I'd seen "Pale Rider". After I got it, I realized Eastwood was using a Colt .31 :banghead:, but hell, it went well with my ROA. Didn't have a .44 Remmy at the time, either.
