I don't know about the larger caliber barrels or .357SIG barrels, but in the Glock factory in Austria there's a display with a Gen1 G17 with a certificate next to it. The certificate is from the Hirtenberger company and it states that they ran 348,210 rounds through that G17 and only had to replace the springs in the process. I don't know why they stopped at that round count, maybe they figured going any further was a waste of time.
Last time I heard, Chuck Taylor was closing in on 300,000 rounds through his G17.
I used to shoot USPSA & GSSF with a guy who worked at Glock many years ago. He said he owned a G17 (at the time I was talking to him) which had previously been used at Glock, Inc. for R & D. He claimed the gun had about a million rounds through it & that it still worked well. I did not ask about springs, etc.
As far as I know, he is a truthful person & the round count is real. Tenifer is a lot harder than lead, copper or brass.
This may not be a smart question, but it is sincere. Is there anything secret, high tech, metallurgically brilliant or magic about Glock barrels that set them apart from Sig, S&W, Ruger and other top gun builders? I'm not hi-jacking, just adding another twist to the OP.