just a oversized soft lead ball or any soft lead around .360 size should work, without know your barrel size its impossible to point you in the right direction but it's not uncommon for some guns to be .357 or .358 so a .356 bullet wouldn't work. Say your barrel comes back as .356 that means at a minimum you should be running a .3565 bullet but .357 would be better as .001 is the standard but there is nothing wrong with going bigger as long as it doesn't cause issues chambering.