There are other aspects that most people don't realize. First, dealer discount on new guns generally ranges from 10 to 20% of MSRP. Then the dealer is always asked to discount the new guns, reducing his margin to nothing. Just maintaining an adequate inventory chews up massive amounts of money, and it just sits there until a gun sells, then most of the money that comes in has to go right back out again to replace the inventory item that was just sold. Nobody can make money on new gun sales. Where can a dealer try to make money? Used gun sales - but remember, the dealer effectively makes his money (or loses money) when he buys the gun - buy too high, with consideration to carrying costs, overhead, the time that gun will sit there until it sells, etc., and he must offer significantly below "retail/market" price, whether it is a junky old Taurus or a desirable/collectible S&W. Honestly, the offer of $350 for a Model 57 (especially with rubber grips) was quite generous, as a 57, although desirable to most of us who frequent the forum, is not going to move quickly in a typical gun shop. Most people are looking for plastic-fantastic semi-autos these days (yuck), and revolvers, other than J-frames and their competition, are anything but hot sellers. Add in the fact that the .41 Magnum has never attained widespread popularity, and ammo selection is limited, availability is poor, and cost is high (remember, the vast majority of the gun buying public does not reload), and the dealer is going to watch that gun sit in the case for months, possibly years in some areas, and every day it sits, that $350 he paid for it is being added to by a pro-rata portion of the overhead - rent or mortgage payments on the building, salaries to employees, utilities, taxes (real estate, income taxes, etc.), maintenance, and many others, and you can see how the dealer's $350 basis in that gun may very well become an effective basis of $450 to $550 within a relatively short time. If he sells it for $600, after sitting on it for 6 months, his profit margin on that gun (assuming he now has an adjusted cost basis of $500 in it) equates to a 20% profit, which isn't really all that much. Most shops would have offered quite a bit less, probably in the $200 - $250 range. The truth of the matter is, unless you absolutely must have some cash immediately, never sell a gun to a gun or pawn shop, they have to give you a much lower price than what you could get if you sell it to another gun guy - it's always been that way, and always will be, 'cause it has to be. They're not trying to do you dirt or insult you, it is just the requirement of being in the gun business.
Buying used guns at anything over 40-50% of "retail" is a sure recipe for going out of business. Sort of like a friend of mine who went into the business of buying and selling used business jets - on every deal, he "bought high and sold low," lost over $40 million in the period of one year (then he kept trying for another year or two, and the banks that had backed him kept lending more money - millions and millions - in hopes that he would "turn the corner" and be able to start repaying the money. Of course, it didn't work, they were only loaning the money in order to try to recoup a bad initial decision, because there was just so much money involved. Of course, it didn't work. He didn't take into account the expenses involved in his operation, so, on the rare occasion that he sold a jet for more than he paid for it (rather than taking a huge loss on the face amounts of the deal, which was more typical for him), he still never actually made any money, as the expenses of his office, hangar space, fuel for the jets, hired pilots, etc. just ate him up. A gun shop is no different, except for the amounts of money attributable to inventory, maintenance and overhead. BTW, just as a humorous aside, I returned from a trip somewhere in my airplane one day and refueled the airplane. My friend had been trying to get checked out in a Lockheed JetStar (a 4-engine bizjet built in the early '60s which was a major fuel-guzzler), and had been shooting touch-and-goes in it with a crew and instructor pilot. We both got to the front desk of the FBO at about the same time, my fuel bill was for about 70 gallons of 100 octane avgas (I had just returned from SoCal), his was for 5,400 gallons of Jet A. I got my bill and paid while he was standing behind me with his Amex card at the ready, and when he heard the two totals, you could just see his expression of "what the heck am I doing this for?" Of course, the ego factor overrode that consideration, and he kept on doing it. The banks finally turned off the spigot, his corporation declared bankruptcy, and he went on to fail in numerous other businesses and pretty much squander a huge trust fund set up for him by his parents.