Gary just beat me to it. Yeah, the wall thickness should be fine. Are you shaping the profile of the outside, or leaving the full 2"? General rule of thumb for powder loads in small bores is a MAX load = bore, so 50gr for a .50 cal. You should work your way up to the ideal load for it, though, since ideal loads aren't usually the max. Starting around 25gr is a good idea.
Others will offer more (and likely better) advice. Please post some pictures if you can!