Hi. Today I spent several hours rechambering one of my 223 Axis rifles into a 22-204. Cutting the new chamber was kinda easy using a PTG 223 AI reamer. I got it exactly where I wanted it. However when trying to set the bbl into the receiver, I had some issues.
I do not have the go no-go guages. I have several sets for 223, 223 AI, etc. I know better than trying to use just new brass..... I tried, paper, labels, etc. Unfortunately, after a bolt closure or two, it was useless.
So, I had a thought (always dangerous at my age)......... What about using a set screw from inside the case? I have a large number of setscrews and a 10-32 'cup point' screw looked perfect.

I took a 22-204 case and drilled a #21 hole through the primer pocket. Made sure the case bottom was flat and burr free. Then I tapped said hole with a 10-32 tap, being careful not to fully form the hole, so the set screw had some friction and would be 'tight'.
It worked perfectly! I used a regular 22-204 case as a 'go' and the adjustable case as a 'no-go'.

There are a couple of caveats here (ain't there always?)

1. I have a lathe for the drilling and tapping operation.
2. I have several good depth guages B&S, Starrett, etc.
3. The set screw MUST be a 'cup point' since it has to straddle the firing pin hole.

Wadda think????

ron