That's a great report, thanks for sharing! You can stone the latch shelf on the barrel, I use a fine stone from a Lansky knife sharpening set, it's easy to maintain the shelf angle with it, just polish the latch engagement surface, it does the same thing as lots of shooting and opening/closing the action would do. I have yet to have a pop open on any barrel that I've done this to when fitting used barrels. You can check the latch engagement by removing the barrel, cleaning the latch and shelf, then smoke the latch shelf on the barrel with a candle or lighter, install the barrel and close the action, open it, remove the barrel and look at the mark in the soot, you should have approx 1/8" or more of engagement.