I see how you did it, thanks! I have enough brass to make this type of jig. The barrel when screwed in angles upward slightly, enough to be noticeable....if your looking! It would be a problem though to accurately chamber it. I have to get a reamer, rent or buy, and preferably 'short chamber' the barrel, while off. As far as the tap, I ordered it off ebay, Merlin Tools, China.....of course. In my research, it appears 1/2-18 is used in some auto applications. Supposedly.....they say....a 1/4NPT is the same,those taps are tapered. I think I will wind up grinding the tap into a bottoming tap. the taper may have caused the problem to start with. I will mount the receiver on the lathe as you have. I've had various C96's since I was about 14.....could buy them then for $25....nobody wanted them. Top drawer Luger, $100! Thinking of the guns I've sold....I just hate myself!