RE: Improved Modern Minie
while the design might be different, the diameter is the same. .575 for a diameter whether it is the traditional, the improved, or modern minnie. There is an oversized minnie of .578 in the improved molds. At least that is getting a little closer to your bore, but I just have a feeling they will be too loose. Then again, you might try them and they might shoot just fine. You can never tell with these rifles.