So I traded off my Mossberg 500 for a 930 and coughed up some cash on my end. Turns out to have been a mistake on my part because the guy who I traded/bought it off of claims it ran fine, so today I took it to the range to try and run a nice mix of shells through it to see how it reacted. After the first shot I realized it wasn't extracting the shells fired. I kept running different shells to see if it was the ammo or the gun. Every shot was a FTE. After giving up trying to run it, I took it home and stripped it down. Turns out the Gas Assembly Piston was missing, even though the previous owner claims he ran 200 + rds through it seamlessly. Now I am stuck in the predicament of trying to get a new Gas Piston Assembly and get ahold of the previous owner to see why this was never mentioned and maybe try to get my cash back from the trade. Is that wrong of me or am I in the right for pursuing it that way since it was stated the gun worked and ran fine?