I gave up on auctions years ago, never got a deal.
Once, I went to the old neighbors estate auction many years ago. I liked the old guy, he treated me well when I was a kid and I wanted a little something to remember him by. He had some guns (nothing special, except that Sako, that's another story).
One of them was a Colt Huntsman that my dad saw the oldtimer dump a running fox with. So I decided I wanted it. To make a long story shorter, after the smoke cleared, I ended up paying just about book value for it. All the guns went high, many way too high.

At most acutions you are likely to pay MORE than the item is worth.  This is a phenomenon called the "winner's curse".  

Because there are a number of people looking at the same item, they will all judge what they think it is worth, and will decide how much they want to bid (based on that).  Those judgements will follow a normal (natural) distribution, with some judgments being too high, and some being too low.  Obviously the person who is willing to pay the most is the person who has overjudged the value of the item, and that person will win it - probably paying more than it is worth.

However, this doesn't have to be the case if there are a small number of buyers, or if the buyers are not well informed or are unfamiliar with an item that you know much about - so it is possible to find great deals - but most often you pay more than things are actually worth at auctions.

I only bought one firearm at an auction. It was a model 60 Cooey .22 bolt, repeater. It was in very good shape except the bluing was worn off completely. It is a very accurate rifle. There were 2 old model 94 Winchesters there.Both had the curved butt, octagon barrels and saddle rings on the side of the butt.I can't remember the calibers but they both went for over $300. That was around 20 years ago. Having worked for an auctioneer when I was a kid I can confirm that things go for crazy prices. I think it's mostly the fact people get caught up in the "thrill of the hunt".