Seeing that I'm getting back into BP with my 45-70 and deceided to get a compressor made by one of my shooting buddies who happens to be a machinist Anyway yesterday I bought a 7/8-14 bolt ,he cut off the head and turned down the end to about .447...works fine, easy to aligne the plug in the case seeing it's visible and not in a die and it cost me under $5, it scews directly into my press like a ordinary die, here's a pic
Bob