Squaring & Lapping the Upper Face

[MikeGideon]

I don't know what depth was cut, but it wasn't much. I assume the threads are cut the old fashioned way, which could easily distort the front surface of the receiver slightly. I also have no idea what the error angle was before I started.

Honestly, I bought the tool because I was more concerned about breaking bolts than accuracy. I was assuming that the great bold famine was gonna continue. Now, I even have a hard use spare on the way from AA.

BTW, I got my two billet receiver sets in a group buy, so they were only slightly higher than forged.