Years and years ago, I bought an antique lever action Winchester shotgun at a gun shop. Don't recall the price any longer, but a few years later I was hard up for cash and went to sell it, getting a LOT less than I paid.

I learned what "rebluing" was that day, and how drastically it affects the value of an old gun.

Only one I will ever regret was selling my great grandmothers mint condition savage 99 in 250-3000 back in college. I dont even like typing this it pains me so much

I pretty much regret every firearm I have sold.

I've never sold a gun and have only traded once. I traded a Sig P226 MK25 for a home brew 6.5 grendel. Don't get me wrong, I like the grendel, but that Sig was one sweet shooter and I regret trading it.

Years ago I sold off a 410 double barrel that my pops had left me. Totally regret it but at the time I had to do what I needed to do for the ol mighty dollar.

Sold an original Ultra light Arms excellent condition low round count in .243 that Melvin Forbs built for $1250. Mentioned that to my buddy (Jon Trammel) and we/he had a good laugh on me. Oh I've got more to come.