I did a similar build in a Striker for Illinois to be handgun legal, since no centerfire rifles can be used and other associated rules, in 30 Bellm. I ordered a 30 Cal blank from ER Shaw, McGowan is probally cheaper, and sent it to Mike Bellm for the chamber. Your build should be easy just find the reamer. I headspace my 30B with an empty case.
http://www.bellmtcs.com/store/index.php?cid=106