The expression "lock, stock and barrel" goes way back, and is directly related to the manufacture of guns. To assemble a complete gun you need all three parts:
- The lock - the firing mechanism (along with the trigger)
- The stock - the wooden parts of the gun that give it its shape and make it easy to hold
- The barrel - smooth bore or rifled (complete with breech plug)
If you have all three parts, you can assemble a complete gun. In colonial America, a person wanting a gun might have gone to a gunsmith for a complete firearm, or might have purchased the barrel and lock and created the stock him- or herself.
The stock is a fairly intricate piece of carving. It has to accept the barrel, the lock, the trigger and the trigger guard. In the following two pictures you can see the necessary woodwork, and you can also see how the trigger and the lock fit together in the stock.
When you pull the trigger, the piece of metal within the stock pushes upward against the sear pin and releases the tumbler so the hammer falls.
A complete gun also included several decorative brass fittings for the nose and the butt of the gun, as well as a ramrod and a ramrod holder underneath the barrel.
The main challenge in assembling the gun, besides the obvious woodworking talent necessary to carve the stock, is getting everything to line up. The barrel has a hole in its side and the pan of the flintlock must align perfectly with it.
The hole in the barrel is tiny. It is hard to see in the picture above, but it is in the middle of a screw-in piece of this modern flintlock reproduction.