I have only sold 2 firearms. A mosin when I needed more safe room (I have 5 and it was the one I was least attached to) and a Chinese sks to a buddy of mine. I do miss the Chinese sks, but I sold it on the condition he sells it back to me if he ever wanted to sell it!
+1 for the Ruger single six, mine had the 9" barrel and the interchangeable 22mag cylinder. That revolver shot like a dream, it was miraculous some of the shots I could make with that piece. Sold it when I graduated college to help by a fiberglass camper shell for my p-up truck because I was moving to Connecticut and had o pack all my stuff......I couldn't rub 2 nickels together when I graduated college.....but I didn't have any student loans either!
I miss the $109 Yugo SKS's, Swiss K31, French Mas 36, Swedish Mausers, 8mm Mausers, and other rifles that I bought all for $109 each plus shipping back in the early part of this century, circa 2004.
Ruger .44 Magnum Bisley Blackhawk. I pawned it and another .44 Mag BH because we needed the money for medical bills. They were my Cowboy Action revolvers, shooting .44 Special rounds at matches.
Grandpaw had bought a single shot 12 gauge for me when I was a teen and rabbit hunting, Thing killed on both ends, Glad it was loaned out and never returned!
I miss my Remington 660 in 243 with 4x12 bushnell scope; used to make 'red mist' out of armidilloes on the pipelines.
Regret getting rid of s & w mod 57, 41 mag, had a 4" blue and a 6" nickle