How is the arm going to lock in place if the shot bolt doesn't line up with any of the holes (which it is likely not to)? Also, that bolt is going to be under enormous shear force, especially being that close to the centre of rotation. I really like the idea of a two stage axe/crusher, but think you need a different way of locking the rear arm to the chassis that is both far stronger and will work no matter what position it's in.