Firearms Values

What are you using to assess the value of your firearms? I'm certain the pro appraisers must use some kind of published, software, or on-line reference.
Thanks in advance!

I have not found a good (free) online resource for gun values. If in doubt I grab the Blue Book of Gun Values. Otherwise I check gunbroker and other online sites for like firearms and compare conditions.

If your talking run of the mill factory stock firearms then the blue book of gun values is what most dealers use as a rough guide, even those prices can be above or below market value. If your talking custom enhanced guns for this sport then it has a lot to do with who built it or the gunsmith that reworked it and its a buyers market and whatever someone is willing to pay to own a particular gun. Some of these guns are testaments to a gunsmith that is no longer with us or no longer building guns and may be worth double or more than the same gun worked by someone else.