I know that the BM 59 mags are rare and more expensive than the M14's. But since I've never handled one, can anyone tell me, how different are the dimensions? Can a M1 that was converted to BM 59 mag fed, be modified to take M14 mags instead? I figure one mag must be bigger than the other so it ought to be possible to convert one of them to the other but not either one to the other.