Upvote:3
When farms were foreclosed in those days, they were foreclosed by the bank, and the bank immediately established some kind of auction to sell off the assets. And the Farm Holiday Association organized farmers to come en masse to these auctions and to bid one cent, two cents, three cents, three bids as a legal auction. They took with them various weapons of persuasion - pitchforks, hunting rifles, knives - and were able to compel the success of the penny auction so much so that auctions were often stopped in mid-stream before they could go any further. NPR.org (emphasis added)
"weapons of persuasion" might be the most useless term I've heard today.
Later, when the bankers would try to sell off the farms at public auctions, the previous owner and the rest of the community would show up... with guns. funny.co (the image doesn't show guns, but the text asserts that guns were present.)
Google image search might be helpful. I would be a lot more confident of the answer if I could find an image.
OP asks for a primary source - I think that is unlikely; intimidation of that magnitude is probably illegal, and I think it is very unlikely that anyone would have been charged for an action that the community so strongly supported.