I was visiting a friends shop the other day and he had a M2 barrel....damn thing was the size of a Mack truck axle.
'course seeing it made the wheels start turning, but never gained any traction.
years ago I saw one mounted to a tripod, and the guy had made a cap of sorts that screwed onto the breech with sort of a cannon cocking mechanism where he's un-screw it, stick a round in, screw it back on, then give it a yank. I never saw it in operation, but it was innovative.
So back to the question at hand: what can you do with one short of having a M2?

+1 find a reciever and maybe just maybe cut it down a bit. Depends on alot of things such as the stock and action. Are you sure its in good shap? Cant fathum way a non burned out barrel would be by its self unles it was a turd barrel or something. Just be sure its ok before you sink any money into it.