Doug Turnbull can do that conversion on a Browning 71. I explored that very conversion a couple of years ago. They could do it on either a Winchester or Browning 71.
As far as bullet limitations, there really are none if you cast your own. The 50-110 would be well suited for cast bullets. As such you are only limited by your own imagination. Accurate Molds will work with you on just about any design you can come up with and MP Molds and NOE have a few options. I have a few molds for my 500 Linebaugh, one an MP 525 grain with hollow point options. Cast hard in the solid option and driven to the rifle and cartridge's potential, that 525 ought to make a serious thumper. Toned down a bit with a softer alloy and in hollow point form and you'd have a good deer, elk and moose bullet.
