Update
Last night I went back to my buddies and went over the gun with a fine tooth comb. Thank you johnch, the mag tube was black, regular wiping did not remove the carbon, it required scrubbing with a scotch brite pad. I also noticed that in the channel that the "arms" of the bolt ride there were a few small burrs. I stoned the guide channel with soft Arkansas stone lightly. I had to assume that like any semi-auto, the burrs could catch the guide rails slightly and cause the bolt not to close completely. We re-assembled everything with care and good golly miss molly it worked like a charm! Guess the blame falls on us mostly, but I don't think the burrs helped us out any. Thanks again for your help johnch, you are the shotgun man! My opinion though is this, spend a little extra and buy a higher quality shotgun, esp. if you want an auto loader.