I have tried bidding on a similar auctions site called invaluable.com. They have some great C&R stuff, and the bidding ends up about what you might see on gunbroker, but they have a pretty high fee that the auction house takes (the "Buyer’s Premium"), quite a bit more than gunbroker does , and I have not seen any real bargains to be found. I was bidding on some m1 carbines, and while the bids ended up seemingly lower than you'd see on gunbroker, with the "Buyer's Premium" the prices did not look significantly better.