Here are three Sheridan 12 gram quick lever changers, the top changer (disassembled) of the three (in the first picture) came with the Pursuit Pistol I posted earlier today.
The middle is a Palmers Pursuit Shop Quick Silver and the bottom is I believe a WGP Q Changer.
Bottom picture show the released state of both the Quicksilver and the Q changer.
The disassembled lever changer (or twist changer) would just use a turn of the rod to move the back piece forwards and backwards. I remember testing it a few times but can’t remember how well it worked.