My gun,Mossberg 500 12 ga, I use for dux(plus everything else) gets completely tore down 10 times or more a season . It's alway wet (or ice) ,muddy ,got leaves and crap in the works,getting thrown around in boats/blinds etc. Duck hunting is harder on guns than any other type. I can take that 500 down and put it back together with my eyes closed. The only part I've never taken apart on it is the trigger group, but it's all right there so really no need. The Mossberg gets looked down on by folks but it's one of the best there is. It always works and any part you could need to replace you can get off ebay, though I've never had a part break. That ole smoke wagon has been through the wars for sure in the last 30 years. I did rebuild some of the inner works like the lifter, interrupters just incase but not because the old parts failed. It's made so simple even 6 year old could tear it down and put it back together. No telling the number of shells that have gone through it, you can push the release button and give it a nudge and the slide will fall open on it's own. I'll post some pics of it on here sometime.