Mossberg 500 problems

Previous to this foul up, I was working on Single-Hand manipulations for an hour or so with this shotgun. I was getting ready for bed when i noticed that something didnt look right. If i would have needed to employ this gun for Home defense, I would have gotten one shot, and then I would be wielding a 7lb club. This concerns me. I will continue working with the 500 to see whether this was a fluke, or that the 500 needs to be reconsidered from its current home defense roll.