You are watching the birthing of a .75 caliber Dutch Snaphaunce Musket with copy of original 16th century lock.
That elegant piece of walnut with perfect grain running through the wrist cost more than some modern rifles. You can see the outline of the lock installation on the musket if you look close. The simple furniture will be forged iron.
This Dutch snaphaunce lock copy is 7 1/2″ long. It has a horizontal sear, like a wheelock. The makers intaglio mark is at the rear of the lockplate. It was probably designed in the early part of the 1600’s. After 300+ years, the thing still throws sparks.