I had a 1945 Ithaca with a Colt WWII slide, that had reportedly been rebuilt by an old Army Marksmanship Unit gunsmith. It had the works- tightened slide/lowered frame rails, 7-digit NM barrel, Micro sights, adjustable trigger, etc. It was exceptionally accurate, but had been shot just enough to loosen it to the point of being reliable. I put high fixed sights on it and replaced the match trigger with GI components... carried it on duty for a number of years.
I also used it during a week-long NRA LE Instructor school in 1991, where it digested 800 rounds of 200 grain SWC--in 100 degree heat--without choking even once. I have no idea how many rounds went through that gun before I got it, but during the time I owned it it burned at least 7-8 pounds of powder. The only thing I ever had to replace on it was an extractor.