Difference in brass size. However since I don't have gauges I will have the smith doublecheck to make sure that there is a problem in the barrel, and not somewhere else. He has the measurements from the AT and can compare to the AT-X
This barrel on the AT-X seems to have more headspace than when it was on the AT, so my brass got around 6.5 thou longer. However I am going to have the smith measure the AT-X and compare with the #'s from the AT so we can see if it was that or some other mistake I made.
...Normally its some mistake I made somehow along the line - either in resizing or something...
Also, I am not a normal AI shooter, normally I shoot a Bighorn TL3, and have shot a few AI's over the years, but none consistently. I have however high hopes for the AT-X since it solves a lot of the stock/chassis problems I didn't like with the prior AI's... Isn't it common for the AI barrels to work across platforms, or is there a lot of variation? I kind of assumed that if they had a swappable barrel then headspace should be consistent across the platforms? Was that a wrong assumption?
That's not out of the norm difference in size. My AI's headspaces about the same amount shorter than what is considered "spec" from AI. It is fine. Just shoot the brass and bump it .002 from the new measurements. No worries. I wouldn't go and bump the brass back down 6.5 thou each time but blowing it out then bumping it .002 is no issue.