I have never seen one on a Contender, but I used to have one on a T/C Renegade.
It was made by TC. The bottom base stays on the barrel, you grab the scope and pull backward and tip the front of the scope up and it and the rings seperate from the bottom piece. The theory on a muzzleloader was that you could take the scope off when cleaning with a bucket of water and not get the scope wet. I suppose on a Contender it was to move the scope easily to a different barrel since you bought the mount in two pieces and could have more of the bases than rings. I still have the boxes mine came in, they now store other parts. It was called QR Rings & QR Base.
I took the scope off my Renegade every time I cleaned it and it always stayed sighted in. It was a pretty neat mount, but was heavy. Although I question the value of the set-up now, TC did make some innovative products through the years. Wonder if they will keep that up since S&W bought them or if it will be status quo.
