I occasionally have a rifle that I just don't use anymore, or need, and I'll sell it. I'm not alone.
Properly setting up the optics on a rifle can sometimes be a challenge, getting the height and position (front to back) just right. Rings and bases aren't universal, neither are ergos on a rifle. I like to pass on a decent set-up. Why should the new owner have to go through the rings/bases selection process again. Often I'll try and sell with the scope if the set-up is good. I sold a 300 Win Mag with rings, bases, mounted optics and a box of ammo, all sighted in for 300 yards. It was a good combo, why take it apart. I could have made more money parting it out, but for me it's not about maximizing the dimes.
If I have a turkey of a rifle, one that no matter what base and ring combo you put on it the ergos are just wrong, I'll usually sell it without any rings or bases. The new owner knows the optics set-up will be on him. I will not mount a scope on a rifle to gloss it up for a sale. Most buyers aren't willing to pay for optics, but appreciate the rings.
Nitro