Be more trouble than it's worth, and quite expensive. Besides, it's a hunting rifle and only the first one or two rounds are important. The rest are merely there as convenience, to keep from wearing out your pocket.
Contact Winchester or whoever they are that manufactures the Mod 70 and see if you can get your rifle into their custom shop. the web site has the parts list and shows a detachable mag setup, but the parts can only be installed at the factory.