I've converted 2 Mod.64's into 64B's. Western Gun Parts used to carry the kits and if you have basic tool knowledge, it's a no-brainer. The original mags were nylon IIRC, not plastic. Nylon was the new miracle product at the time, but the magazine became friable (brittle) over the years and started to break very easily. The only part that had any challenge to it was the metal mag well plate. With some patience and small Dremel grinding wheels, I reconfigured the plate to accept the new mags And to confirm, the Savage mags work just fine.