Blue book is nice I guess but, just like cars, it's never accurate. Anything is only worth what someone will pay. That being said, what Dale and I do as well as most any other FFL that buys guns does is look each up on Armslist, Gunbroker and one other local site of your choosing, which ever site is appropriate to the gun. Then average the 3 prices. Armslist gets you the going asking price, Gunbroker gets you the final selling price. Gets you real prices that people are actually paying, not what a book suggests one might pay.