I have a very well used 870 express 12ga. (actually my first "big" gun I got when I was 15) that has an issue. This gun literally has 10000's of rounds through it and has the war scars to prove it...lol. The piece that screws over the magazine tube that holds the barrell on is loose. It will tighten down but works its way loose after a couple shots. I don't feel safe shooting it. I thought about using some automotive Lock-Tight on the threads as I think they are just well worn on the magazine tube. Didn't know if anyone has had this issue a solution?, or has used anything like this on a firearm.
I thought about just buying another 870 , but this gun just holds way too many memories of my Dad and my youth.