+1 on Guns Galore, I drive 160mi round trip to shop there.
I got a perfect SA TRP in SS for $825, I called Springfield to ask about warranties on used guns, they said it would not be covered but they would work with me in the event of an issue, which there was none.
At Cabelas I picked up an old HK P7 PSP for market price, what I liked about that buy was that they gave me 30 days to decide if I wanted to keep it.
I didn't even know Gander sold used guns, I will check it out.
Finally, there is a new Sportsmans Warehouse in Allen Park, small selection, fair but not great prices, and no used guns. But its only been open about 3 weeks.