Been shooting lots of different Glocks since '93: g17, g21, g22, g23, g24, g26, g27, g30, g31, g32, g33, g35. I've put most of these guns through some heavy testing with reloading experiements, etc. DANG IT! I just can't seem to blow a Glock. I have no idea what I'm doing wrong
Some of my testing is documented at my site, for example using my G31 for extreme bullet setback testing with 357sig ammo.
I'll just keep trying I guess
For some strange reason, I've also had good luck with my Beretta's, SIG's, USP's, CZ, Kimber & Colt 45's, and even my Steyr pistols.
Regarding SIG and Glock chambers: The 6 o'clock chamber opening is just one part of the picture. Check out the pressure ring after shooting full power loads. My SIG's ususually measure around .428 while my Glock .40's measure as high as .432. Obviously, the Glock has a much looser chamber, at least based on my humble use of a caliper. The aftermarket Glock barrels do have slightly tighter chambers, as well as often having slightly less exposed brass in the chamber opening, which brings the pressure ring down to .427 - .428 usually.