I am not sure I agree 100% on some of the full disclosure here. Not to say that I don't disclose everything, actually I usually am a bit too honest. If I sell a car, I will tell people exactly what I think of the condition. I told the buyer of the last car I sold that the engine had a knock, even though they couldn't hear it because it was summer, not winter.
With guns that "don't shoot" there can be a million reasons, many of which are not the fault of the gun. I have had a gun or two that I thought didn't shoot, right up till I found a load that the gun preferred. Should a gun be worth less if it doesn't have a proven accurate load? What about new guns? Few are provided with any proof of accuracy. With hunting rifles, I don't see people posting targets with used guns and asking for a premium price. Would many people pay extra for a gun with excellent looking targets?
If I knew that a gun had a shot out barrel, or a mis-aligned scope mount, I think it would be right to point that out. That is an objective description. But, to offer a gun for less money because I had not found the right load for a gun that otherwise had no known flaws seems to be saying that the accuracy issue could not be my own issue.
Most of us know of a gun that one person couldn't make shoot and in the hands of another was a tack driver. When I shoot at the deer season sight in days at the range, I see lots of guns that won't hold 3" at 100 yards. Lots. Is that because all these guns are no good?
I don't remember seeing any postings in the classifieds like this:
"Model 77 243 tang safety. Poor groups with all loads tried. Several scratches that can only be seen with a magnifying glass. Knocked over several times by my clumsy labrador with no visible damage, but I think it must have damaged the gun. All my other guns shoot 1/2" groups, so rest assured that this gun will not shoot without major work. $400 FTF, or $435 shipped in ConUS.
Labrador Retriever also for sale. Dog doesn't hunt and seems kind of stupid. Eats too much, and has excessive gas. Price negociable."