Rolling_block
Rolling block
Firearm action, subclass of breech loader
A rolling-block action is a form of firearm action where the sealing of the breech is done with a specially shaped breechblock able to rotate on a pin.[1] The breechblock is shaped like a section of a circle. The breechblock is locked into place by the hammer, thus preventing the cartridge from moving backwards at the moment of firing. By cocking the hammer, the breechblock can be rotated freely to reload the weapon.