Generally about 1 month prior to deer or elk season. This is how it happens: the owner of a Never Miss Magnum is at the sporting goods store to buy some much-nneded supplies for his upcoming adventure to The Wild Back Woods in search of the wiley deer or wapiti of his dreams. While there, he decides to eyeball the local goods in the Department Of Firearms. Suddenly, he is transfixed by the Absolutely Never Miss Super Magnum with the flashy hang tags. At exactly that same moment, through the miracle of hyperspace, his Never Miss Magnum fails drastically and totally and needs to be replaced immediately if his adventure is to be a success. The owner of the previously never-failing rifle that has suddenly gone bad realizes it will be a great sacrifice to part with his trusty old friend, but reluctantly takes up with the interloper and abandons his old rifle in its hour of agony.
But never fear! Before you shed that bitter tear, hear, hear!! Through the magic of Gun Shop Man, the rifle is suddenly reborn into a never-failing masterpiece of technology at a significant investment of technology known only as Gun Cleaning Kit, and returns to the gun rack to mystify and mislead another hunter within days. Oh, glorious day! Happy ending!! (birds twittering and chorus singing as the light fades).
In other words, most rifles don't wear out.