I am the proud owner of an 870 LW designed for 3" 20 ga shells. I've done a thimble full of gunsmithing over the years, sort of like a hobby. I wanted to slicken-up my gun so I dismantled it and began polishing the parts that rub, using 2000 grit wet-or-dry paper. I'm a bit perplexed over the fit of the slider assembly (diagram part no.57 according to some older diagrams) inside the receiver. As y'all know, the piece sits in some notches along the top of each pump rail, and is "sandwiched" by the lock bolt when everything is in place. Mine has what seems to me like a lot of "slop" in that it feels like it's maybe .30" inch or so narrower than the side-to-side distance between the pump rail grooves when placed inside the grooves of the receiver without any of the other action parts installed. My concern is that it might soon wear out since there's little "interfacing" between its "wings" and the receiver lands when being forced upwards as it rides over the hammer during the cocking phase. Is that a design feature? If so, why would it not work better and last longer if it was a bit wider?
smoke-pole