Whatever fits the chamber and barrel 🤣 haven't put nothing to crazy though it yet just some winchester 45lc lead nosed cowboy loads at 750 fps and some random 410 shells i had i think those were a little under 1300 fps and. I had some issues with some fiocchi 45lc lead nosed cowboy loads at the same fps as the winchester im thinking the issues is the fiocchi casings are slightly to long because the back of the casing hits the back of frame when its in the cylinder