Takedown screw lock plunger spring ORIGINAL model 1903 and early 63 Winchester semiautomatic rifles. This spring sits under the takedown screw (wp23-a) LOCK (wp153-a) and puts tension on it to keep the takedown screw from turning. The later model 63's removed the lock and went to just a plunger (wp154-c) and spring (wp154-d) that can not be seen from the outside. Both styles use the same pin to hold the lock in place (p160)
