Beleive it or not, a lot of good deals can be found on Gunbroker.com if you're patient, and willing to do a lot of searching through pages of rifles. That's how I found that AR, and right after I bought that, I began bidding on a Johnson Automatic 30.06. I could only go to about $1100 cuz my gun budget was blown on the AR, but it sold for only about $1600. At that price, it was a great deal!
Most of what gets listed there is for sale by dealers and they aren't going to give anything away. But once in a while, someone lists something good, and doesn't set a reserve price on it, and if they don't put a bold or "In the top" listing on it, it may gone unseen by most of the bidders. That's when you have to be ready to strike.
One mistake I have made is forgetting to check back on an item I'm interested in, only to find that the auction ended, and I never did get my bid in. I usually don't bid until the last hours of the auction because I don't want to bring anyone's attention to the item if they see that it's being bid on.
Now, I must get back to browsing GB. :)