Someone on Glock Talk posted a thread about his trip to the factory in Austria. They have one of the original G17's there under glass with 387,000 rounds through it.......
There was a Ruger Security six or Speed six that I read about that had over 1 million documented rounds thru it. It was a rental at a shooting range. If I can find the article I will post it.
Years ago I used to save ammo boxes in my gun closet. after my mom died last year, I was over there going through some of my old stuff and had three large clay pidgeon boxes full of 100 rnd plastic .22 ammo boxes, and 36 500 rnd "brick" boxes. the only .22 I had at the time was a Marlin Model 60, so judging by what I saved, and what I may have thrown away years before, I would say that Marlin easily had 75k rnds through it, and I don't ever recall a ftf or fte. Damn I wish I still had that gun.