I was wondering how old this gun is?

Anthony, from your description and the pic, it looks like you have a Model 5100 side by side. It may not have a serial number on the firearm depending on when it was made so dating it can be fun. Start with the name on it, if it says Springfield / Stevens on it then it was made prior to 1948. That's when Stevens dropped the name Springfield from the name. Look on the lower frame close to the hinge pin, sometimes there is letter stamped on the receiver out side but most of the time it's inside. These are code dates from Stevens, if it has a A it was made in 1949, a B means 1950 and so on until they stopped manufacture.

Just an FYI if you need to order parts for this shotgun and you can't find anything available you may be able to get Stevens Model 311 parts for it depending if it is a Series I or Series II that the 311 parts came from. Good luck.

Thats probably 5100?

The forearm looks rough while the stock looks good. I suspect its been replaced, or at least re-done.

How old??? who knows......you can search google for info based on receiver markings.

You may find something if you scroll through this-

http://www.shootersforum.com/shotguns-shotgunning-...