The Model 1200 Winchester that I bought in 1967, but that hasn't had that many shells though it, is just as you described your 870. It has a 2 3/4" chamber and when I shoot turkey loads in it and have a light grip on the forearm the heavier recoil will partially eject the spent shell and then when I go to jack it on open by hand it is fairly stiff just like I think you are talking about in your 870. When loading/unloading unfired shells while keeping the button on the trigger guard depressed it is as smooth as silk. I think we are experiencing the same thing and my theory is it's just that the spent shell has expanded just enough to cause a slight hangup when it is not completely ejected all in one movement and it makes me doubt there is a thing wrong with either gun. It's just something I have noticed every time I shoot it infrequently with those turkey loads each Spring because that have more poop to them than regular shells that don't cause the action to start opening on it's own. Anyway, that's my theory and I don't plan on doing anything to the gun.
Last edited by Topgun 3006; 06-08-2012 at 10:55 AM.