[mrerick]

It's a good idea to inspect a toggle train for headspace and any looseness (forward / rearward) which is additive along the entire train including the breech block, center block, rear toggle and all the axle pins. There should be very little forward / rearward play perceptible on a Luger, and a headspace gauge should verify cartridge case positioning in the chamber.

As a Luger wears, this play will increase over time and the shock of a loose toggle train being driven to the rear against the frame ears where the toggle locks during firing can cause metal fatigue and failure. Remember that the toggle train operates like a knee joint until it is driven upward against the frame ears during cycling.