Yes. We have one in the shop my boss built. It uses cut off magnum case heads to hold the primer, has a vent screwed into the barrel to get to the powder, and is "Chambered" in the rear for those case heads. It uses Barnes X bullets, pre engraved with a fixture he built so they can be loaded. He uses 460 Weatherby load data to start, and has no problem getting 3000 fps out of a 300 grain bullet. (BTW, it's 45 caliber.) It was lots of work, would cost $4000 at least to have someone build it, shoots great and hits hard. Kind of a silly thing to build, but it does work.
