I got the same shotgun in 20ga, and the scope that comes with it got tossed in the garbage, but if your shooting without the scope it has no iron rifle sights, did you install them? Get a decent scope for it, the Mossberg 500 will not win any beauty contest but they shoot well for a inexpensive shotgun. By no means would it shoot as good or near my Savage 220f.
http://www.cabelas.com/product/Shoot...3Bcat104535180