The fastest money I ever made on a gun was a S&W Model 29 in 1975. Because of the movie "Dirty Harry" every collector had to have one so in spite of the fact that the MSRP was $200.00, they were selling for around $450.00 or so. Montgomery Ward in Anchorage had a raffle, $1.00/ticket for the chance to buy one for $200.00.
I won, took it home and wondered what to do with it. That night at work at Western Airlines, a fellow employee who was a collector offered me $200.00 plus a Super Blackhawk cut down to 4-5/8" with 5 rounds through it plus a box of ammo plus dinner at the best place in town for me and the wife.
So I flipped that puppy and ended up with my money back, a free Ruger, ammo and dinner in one day.