I am looking at a used Moosberg 500A and have never bought a shotgun before so wanted to make sure this is a decent gun. I just want one that is inexpensive so I can get the feel of one before spending more $$$. Besides I like the idea of a beater gun. This particular gun always has the bottom open and I feel like there sould be something covering it. I have included pics of what I am taking about. The second pic has the pump all the way back.