it's an original 1942 .303. if it was an 1960's 7.62 i don't think i would consider altering it. .45 long colt is an interesting idea, it would need a custom made magazine but i don't think that would be to much of problem. local gunsmiths might not have the reamer and that raises the cost even more. the other problem is the cost of ammo, which is why i also suggested the 9MM, bulk from cabelas is a lot cheaper. i know wolf brand ammo gums up the workings of semi auto's, but what about in bolt-actions? i keep them pretty clean so tha might not be a problem