Great stuff, thanks for taking the time to post this, changes my viewpoint on what "reusable" means when it comes to brass.
What ever came in the 20 gen 4, it is stock and new with 20 rounds thru it.Armscor brass isn't as good as others but it is more because of the powder they are using. They are using too fast a powder for the weight bullet that they are trying to shove too fast! That expands the casing too fast and exceeds the brass metallurgy in use. The last Armscor 180 pull down I did showed Tight Group 6.4 grains.
What spring rate are you running?
I could not open the picture on photobucket. Can you resend it with a .jpg picture?I cut open a couple pieces of brass that bulged in my Lone Wolf barrel, to see where the bulge happened relative to the web of the case. This is a newer barrel, bought in December 2011. I thought the picture was interesting enough to post here.
This is a 40 S&W case, didn't have any bulged 10mm handy, but the internal dimensions on the 10 and 40 are pretty much the same other than the primer pocket.