I have HEARD of some of the Ubermags, and back in the day 264 Win in bolt guns, shooting out a barrel in a thousand rounds or so. The only gun I ever SAW that was worn out was a 67A Winchester 22LR bought by my Dad in 1936. The Bolt had a groove worn in the bottom and the extractor was worn flat. We retired it in the late 90's. I know I shot 25K plus rounds myself starting in the early 60's. I do not think one person could actually wear out a Handi under any normal circumstances. We would have to be talking something like aPD shoot with a 22/250 every day for months or years. For one thing , the heating of the barrel would destroy accuracy to the point that it would be useless to keep shooting until it cooled. I could shoot my cast loads in my 500 all day long and it would not overheat, but who would do that? The closest I could come would be a competition trap shooter with one of the Topper Trap guns, and I'll bet 20 years on that.