Not dumb, more arrogant.
Bought a savage long range hunter from a guy that told me he couldn’t tighten it up much more than 1.5-1.75 groups. Told me he tried a lot of different loads. I figured I knew better.
I didn’t.
Bought a beautiful Mauser in a custom stock 6mm rem. He told me he had it for years and it would shoot the first two close and the third would be a flier. Again I figured I could solve that problem. I couldn’t .