Do those proof marks mean that they fired a butt-whomper super-duper magnum anti-tank round through each of the 6 chambers in that gun?
Really, do proof marks mean there is evidence documented in steel that the gun has been abused?
Bart Noir
and to make sure they will withstand an overcharge specified by the laws of said country.
They simply mean the hardware was built to specs and accepted by the government body that ordered them. It's no different than proof marks on military surplus arms.