Austrian Stamp Proof Mark Double-headed eagle with number 4

Austrian Probing Mark applied to a weapon confirming the successful completion of Trials involving the firing of cartridges with a force greater than standard bullets. 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 Vienna in 1892-1938.

Confirmation type: Confirmation for black powder rifles