The one good score I got was pure lucky. I walked into the store and was looking at a Luger (all matching). Price was a bit high, the local Luger exert walked in, gave it his blessing though he had several similar ones and not interested. Going on that I traded a couple of harder to move guns for a fair price. Knowing you are not dealing with BS types is all good (store guy I knew and his take on the Luger guy was right on).

Know your basic stuff or who to trust.