I checked our ML rules and all it says is that it (must be a single projectile loaded through the muzzle having a bore of .44 inches or larger) So it looks like them 10mm 200gr HP-XTP's will be fine. Since I already have about 300 of the 240gr.HP-XTP's how much difference will the 40gr. make??? If I need that little, they should be about the same should'nt they???