I bought the Mossberg 935 (autoloader) with a synthetic stock and all (barrel, stock, forepiece and receiver) camo'd in Mossy Oak, plus a case, gun lock, extra-full turkey choke on the 22 " barrel and a sling at Cabela's for ($569??) + tax. (I think.) It is built to shoot only 3 or 3 1/2" shells, 2 3/4" shells are too light for it. For me, that was the best buy and now I have my turkey gun. I plan to buy a waterfowling barrel for it when they become available (late fall), too, so I'll spend more than your $600, in total to make it multi-purposed. Plus, I'll have to buy other choke tubes if I want to shoot different patterns, as the only choke I got was the turkey choke. So it may not be the best for you. Just depends on what you're really after. From what I see on this site, though, it seems to me the Mossberg 835 (pump) is many people's favorite turkey gun, and I think they are under $400. If you like pumps, I'd take a look at them.

I think the Cabelas store in Owatonna, Minnesota is having a big gun auction this Saturday, of new and used guns, (starting at 10:00 a.m.??)including some turkey guns. You should call them, maybe, and see what they have on the auction list, if you can't get the list elsewhere.

Good luck!!