I have a double gun journal with an article on the wristbreaker ( Autumn 1998). They show several pics and end up with a drawing of a Beesley patent similar to the Purdey, but a little more simple. It doesn't have the pushrods and lifter cams at the action knuckle, but has a pivoting cam that compresses the V spring as the action closes. The author indicates it would ease the difficulty in closing over the Model A ( wristbreaker).

Glad the new Lancasters have Beesley actions. Just wouldn't be a Lancaster otherwise.