We have an excellent group of appraisers here at TFF. They volunteer their services in our Ask the Pros & What's It Worth Forum
. With good photographs and any information you can provide, you'll get reasonable appraisals on just about any firearm in existence.
The guys there are great; I can't stress that enough. That said, if you'd like to be able to look up most everything whenever you want, there is a Blue Book of Gun Values
, just like the Kelly Blue Book for cars.
Welcome to the Firearms Forum! We're glad to have you here.