So we are looking at .006 less than what we expect to see. That could have been removed when they were struck for final finish. I was told that many of the 2" barrels were proofed, then had more metal removed before finish and that would often drop them down to near .020 or less in some cases. Once they passed proof as long as the internal bore was not altered to take it out of proof nobody worried about much it seems.
May I ask what tools you are using to measure your wall thickness and how much confidence do you have in their accuracy? It sounds like you are getting very good results.
