Unfortunately, some folks need a reality check on selling guns, especially to dealers.
1. The profit on a given new gun depends a bit on the maker, but NO SANE DEALER is going to buy your used gun for more than he would pay for a new one or equivalent wholesale.
2. Unless you do a trade, NO DEALER will buy a used gun for what he can sell it for; he has to make a profit, so the seller will be lucky to get 50% of the "market value" as seen in auction sales and gun value books.
3. If you do a trade, your new purchase has to have enough markup to cover a break-even or a loss on the trade-in. Except in rare cases, you will get less/no discount if you do a trade. Better to sell the old gun directly (if you can), then use the cash to buy the new one.
4. There is a cost to just having guns sit in a showcase. Inventory does cost money, one way or another, so it is to a dealer's advantage to turn over his inventory as fast as he can. A gun in a showcase for three years is not helping feed his family.
5. Some day, your Ruger 101 or S&W Model 642 may be a high dollar collector item. Today, it is a used gun, and it is not going to sell for its new retail price.
6. No matter what you see on Pawn Stars, few dealers will dicker. They know the market better than you do, and aren't about to "split the difference" on that old IJ breaktop if you start out asking $2500.
7. There are some guns a dealer won't buy, and won't take on trade unless the new gun markup is enough that he can toss the old gun. He won't take in guns like RG-10's or old junkers because he can't sell them without a guarantee and those guns can't be repaired.
8. Guns like old IJ or H&R breaktops and old "no name" solid frames have a small collector interest but only if in near new condition. Peeling nickel, rusted finish, corroded bores and missing parts bring value down to nothing, as in nada, as in zilch. They are not worth the cost of writing them in the dealer's book.
9. Your trade-in might be in perfect condition (or so you say), but the dealer has to allow for the ones that have been tampered with, broken, or worn out, and his offer will reflect that.
Jim