Breech pin

Breech´ pin`

1.A strong iron or steel plug screwed into the breech of a musket or other firearm, to close the bottom of the bore.
References in periodicals archive ?
Removing the new multiple breech pin differs from the original.
Note the firing pin will need to be pushed into the breech pin with your thumb in order to replace the pin.
Use the firing pin to push out the breech pin (#014) by pulling the barrel slightly forward and holding it there as you push.
Slide the breech pin and toggle out towards the rear of the barrel extension (6).