In 1935 Winchester changed its locking system from using the protrusion on the firing pin as the breech bolt lock to this new system. If you have the new system your bolt will only have one pin on the top right hand side (1 pin bolt).This is a special-made pin that holds the Wincherster model 62 breech block lock for the 1 pin bolt in place. If your pin is worn and missing the HEAD, it can not hold the lock (wp11-b) in place. The lock will then slip out of the the groove in the action slide (wp646), which wallows out the hole in the end of the action slide and rounds down the tip of the lock. This pin also acts as your firing pin stop, and is inserted through the lock on the left of the bolt and into the hole in the firing pin. The pin head is very thin and has to fit between the wall of the reciever and lock. Depending on your receiver wear you might have to take a little sand paper to the head of your pin so it does bind up. You will see this bolt design in the model 62's from serial number 24,002 up to 98,000. I have never seen an original pin that still has the head on it beacuse they wear off. After 3 years of production Winchester returned to the original lock design,
