If you got it at a Gander Mnt why not just bring it back there and let their gunsmith take a look at it and give you a definate answer. I don't think anyone on here would be too comfortable giving you an answer without seeing the gun themselves.

Don't go buying a new gun. There seems to be nothing wrong with the one you've got , you just need to know what you can shoot out of it. If you find it only shoots 2 3/4 , so what. You are a new hunter, it may acctualy help you. Having the lighter load will force you to wait a little longer for a good shot and not push bad shots relying on the extra power of the larger shells.