There are several reasons why someone would want to know the value of a firearm. The most common is either the person is selling or buying and want to have some idea of a benchmark value. Other reasons can be for insurance purposes, dividing an estate, or just curosity as to how much of an investment someone has.
The real answer to how much a gun will bring is much like that of selling real estate. It is what a reasonable buyer is willing to pay. Many seller believe that because a gun is old it has value. That alone is not true. It is all about supply and demand.
The primary reference used by many gun dealers and appraisers is Blue Book of Gun Values. It is available in both a hardcopy and also as an on-line subscription. If you are traveling to gun shows, then you may well want a hardcopy of the book--unless you have good internet access on your cell phone. If located in a single place with good internet access, then the online subscription is a good way to go. The online data is also updated quarterly.
But what are the possible flaws with using the Blue Book as the single "Bible" for gun values?
This is a must have publication if you are going to deal in firearms. I would recommend that you go to the Blue Book website www.bluebookofgunvalues.com and see what they have to offer.
Many people who are not into the firearms business as a profession do not want to spend the roughly $40 or more to get a professional price quote on a firearm.
One way to get a guns value is to go to a local gun dealer or gunsmith. If they can't help you, then ask for a referral to someone who can. Be sure to ask what the charge is for an appraisal before having the value established.
You can also call Blue Book at 1-800-877-4867 and have them do the research for you for a fee. If you have several guns that you are inquiring about, then it might be cheaper to either purchase either the book itself or get an online subscription. One advantage of getting a copy fo the Blue Book is that you might be able to resell the book after you have finished using it. If you are attempting to get values for insurance purposed, then it would be advisable to copy the pages that contain the information that you are interested in and save them in a safe place.