Gun shows, mostly. Gun forums can be good for somewhat unusual or rare items if you are selling them for a fair price. Gunbroker is a great way to sell as well. I might consider Armslist for less rare/collectable firearms.
My advice is don't try to get top dollar for any gun you are selling - price it to sell. Once in a while, if you have something rare that someone else just has to have, you can get top dollar, but that doesn't come along often. If I decide to sell one of my guns, I update my research then price it to sell and end up getting a price I'm perfectly happy with.
Now days I'm an ardent supporter of Cheapshooter's rule of firearms...don't sell any of them.
I don't subscribe to this. YOU are the best one to sell your own firearms.
WHEN you die, and
IF you still own valuable guns (
not average run-of-the-mill guns), your wife, son or daughter are very likely to get ripped off BIG TIME! That old Luger, ugly 1st Gen SAA, Python, and old T-Series Hi-Power - "j
ust a bunch of junky old guns that are hard to sell - I'll give you $500 for the lot of them" is what your heirs will hear from the gun shop they take them to. Yes, even if you keep an updated firearms log that's not going to much matter. So, before you get too old, reduce your own firearms collection to something manageable by an ordinary non-gun-nut person, if you care about getting your value out of them. Or, make lots of babies who will love your future gun collection!