Ok before I lay this out there know this:

1: I am an armourer
2: I am a Fitter and Turner
3: I know this may all be for nothing when what I build blows to pieces on one of my prooving loads

Now then with those facts out of the way I have a nice length of steam pipe at work and have recently been bitten by the BP bug. I am contemplating building from scratch a ML shotgun/smoothbore out of said steam pipe. Its nominal bore is 1" (25.40mm) and I can't see any real problems with doing the build. I have a CVA .45 and man that thing is simple, I'll basically copy its trigger mech with a few minor alterations. Mainly instead of #11 caps I'll use small rifle primers held in a cut down .218 bee case. Suggestions?