I've bought a couple of guns off of gunbroker and everything went well till the last one. It's a Remington 121 that I bought off of a guy from Missouri. Feedback was good but after the auction closed the guy wanted payment sent to a pawn shop. Ended up he was representing himself as a kitchen table FFL but was a pawn shop. Gun also ended up having a broken firing pin and a ring in the barell's rifling. Guy wouldn't stand behind his discription at all and stuck me with the rifle. Gunbroker gave him my phone number as part of my contact info and after I left negative feedback started calling me threatening me in order to get me to change it. I wouldn't and contacted Gunbroker to do something about it.
They deleted his feedback left for me. But also changed my feedback left on him from negative to neutral basically giving the guy what he wanted. The wouldn't acknowledge that they had given him my phone number and wouldn't do anything about a seller that threatens buyers when he rips them off.
I'm off of doing business with online gun auctions because of this. I'd recommend buying from a reputable dealer or local. But that's my 2 cents.