In 13 years of doing this I've never had an action "hit the number" on the thread pitch diameter on the first pass.
-That sounds a little strange so I'll explain:
I use a slant bed CNC turning center for all my barrel work. I use a canned thread cycle called a "G92".
You direct the tool to approach the part, then it starts cutting threads. The "number" according to the Machinery handbook for a 1.0625X18 thread is .995" for the minor diameter.
In all cases (this action being the exception) I have to either bump an offset or write an additional "squeaker" pass to get that silky thread fit that I'm after.
This time I hit it on the first try. Maybe coincidence, I dunno. Don't care either, all I know is its cool when it happens!
Chamber runout was in tenths, .00012" up at the shoulder and .00017" back in the web area. I can live with that I think!
Anyways, I like this receiver. Machine work is very clean, good primary extraction, all the tapped holes look good, the bolt is nice and slick (I think it must be surface hardened, either nitrited, or cased maybe) and the overall presentation is spot on. All the edges are finished and edges broken without being overdone. (rare)
Hats of to Borden. Nice, nice piece.