AB - That is correct, several of the local pawnshops sell firearms on consignment, although I only used one that I like. There are two sticky points of the deal.
The first is that the 20% goes hard as soon as you sign off on it. So if you have a $1000 gun for sale (which he will have on the floor for $1200) he gets $200 whether it sells or not. They don't collect the 20% until it sells or you take it off the rack. When I reduced the prices on my guns, he only charged me the 20% on the new prices when they sold, which I thought very reasonable.
Another issue is that if you do take it off the floor, they also charge a $20 transfer fee since they have to transfer it back to you. The shop had taken custody of it for sale and they require an ATF Form. You would think that would be built into the 20% but I sold at least one gun for less than $200, so I can kind of see a point, even though the transfer is very low cost to them for the employee time.
That said, they do list your items on line with nice pictures at no cost to you. I also like the idea that I am not selling to a prohibited person, even unintentionally I wouldn't want it to come back to me in our litigious crazy society. There is a nice, neat paper trail.
That particular shop won't buy or deal in second hand ammo. After I eliminated a few calibers I took the ammo I no longer needed to another pawn shop where the owner gave me good prices on most. Some of his offer prices were too low, and when that happened I decided to keep it to sell or trade later.
As soon as I walked out the door an employee followed me out and offered me what I was asking the owner for, for the rest of it. They have a store policy that if a client leaves the store (with anything, not just guns and ammo) then employees are allowed to make parking lot deals. I was in the middle of moving and downsizing at the time and it felt pretty good to get rid of all the excess I didn't shoot or use anymore.
