British Stamp Proof Mark Crown GP

An English Probing Mark applied to a weapon, confirming the successful completion of Trials involving the firing of cartridges with a greater force than standard projectiles. It varies depending on the powder used in the test (black or smokeless, otherwise known as nitro) and the type of weapon on which it was applied.

Used in London from 1637.

Confirmation Type: Final confirmation for muzzle-loading black powder shotguns.