I would say it is somewhat common in this area for families to put everything in a sale and then buy what they want. Proceeds are split evenly, after the labor, advertising and percentage of course. Cost of the auction sure takes a bite. I've worked many of these type sales.
Large collection of very nice firearms sold here a few years ago. Owner was terminal and the three sons could not agree on a split. The owner got fed up and watched them all sell. He split the money three ways. I believe two of the sons bought a few.
Guns usually sell high in my experience. I have seen a few "deals" though.
