The first fifty I ever shot was a converted Boyes, in the early '80s. A friend had it, and it shot reasonably well. They are BEASTS I tell you, they weigh a TON.
I'd spend the money on a current production rifle if I were you (unless you plan to DIY), there are several good ones to choose from that are much easier to deal with. I've never seen where a magazine was that big a deal on a fifty, a single shot works just fine. I decided on a Serbu, ymmv.
lpl/nc