This mechanism is called a box-lock because it was built into the middle of the fame while a typical flintlock is built onto a plate that mounted on the side of the pistol or musket.
seen from United States
seen from Russia
seen from China
seen from Maldives

seen from Australia

seen from Germany
seen from Germany
seen from Australia

seen from United States
seen from Sweden
seen from China
seen from United States
seen from United States
seen from United States
seen from United Kingdom
seen from South Africa
seen from South Africa

seen from Colombia

seen from Malaysia

seen from United States
This mechanism is called a box-lock because it was built into the middle of the fame while a typical flintlock is built onto a plate that mounted on the side of the pistol or musket.
Barton box-lock "muff" pistol, made in London
Box-lock muff pistol with screw-off barrel
A gentleman or lady’s companion
Set of folding trigger, ivory handled percussion muff pistols, early to mid 19th century.