Why bubbaize a historical piece? There are a lot of them around, but there also used to be a lot of Mausers, Springfields and Krags around, too. Price any unaltered ones lately? Besides, that is why the rifle makers developed chargers, AKA stripper clips.
I honestly don't see the point. There's nothing wrong with the five-round magazines, and I seriously doubt anyone is going to take a Mosin into combat again to make this worth the trouble...
Yeah, I know there's probably some Afghan tribal warlord who couldn't find an Enfield running around with a Mosin somewhere; but I consider that to be the "exception!"