I've read the following posts and they all basically point to about 4 cartridges. 30-40 Krag, course you can neck up the 30-40 case from 35 caliber to even 375 caliber. Or you might be interested in the 375 2.5" flanged or just neck up the 303 case to 375 and keep that new barrel of your like that way as you can shoot a heap of cast bullets before that barrel even beginnning to show anywhere an appreciable amount of wear.Frank