Seems like a dumb thing for a handloader and bullet caster to carry, an adapter to get lost and another kind of ammo. You could load up a few .30-06 cartridges with 100-110 grain cast bullets and five or six grains of pistol powder and carry those instead which would certainly be more accurate than shooting one of those adapter things. About the only way that would make sense is if your carry pistol was a .32 ACP which seems a strange thing to carry in the woods.