This is a new one for me, I picked it up at a gun show. It says 38-45 B, and the chamber dimensions are consistent with the 38-45 Bullard cartridge. The mold produces a 0.375" caliber flat nosed bullet that weighs about 200 grains. The sprue plate is missing, so the bullet that came with it has a blob of lead on the bottom, and I can't get an exact weight on the bullet itself. Why would Ideal make tools for such an obscure caliber?