The Dragunov is a semi-automatic, gas-operated rifle with a short-stroke gas-piston system. The barrel breech is locked through a rotating bolt (left rotation) and uses three locking lugs to engage corresponding locking recesses in the barrel extension. The rifle has a manual, two-position gas regulator. A gas regulator meters the portion of the combustion gases fed into the action in order to cycle the weapon and sets the recoil velocity of the gas-piston system. The gas regulator can be set with the help of the rim of a cartridge. The normal position #1 leaves a gas escape port opened in the form of a hole that lets some combustion gas escape during cycling. Position #2 closes the gas escape port and directs extra combustion gas to the piston increasing the recoil velocity of the gas-piston system and felt recoil. It is used for when the rifle does not reliably cycle due to carbon fouling build-up in the gas port, when shooting in extreme cold or high altitude or using low powered ammunition.
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