Beretta ARX100 556 x Instruction Manual - Page 17

THE FUNCTIONING OF THE ARX100 When the trigger is pulled the hammer is released and travels forward striking the firing pin, the firing pin travels forward under inertia striking the primer of a loaded cartridge. The primer detonates igniting the powder. The powder burns creating a gas that pushes the bullet down the barrel, when the bullet passes the gas port (a hole drilled through the barrel for the purpose of venting gas from the barrel into the gas system) gas passes through the port, into the gas block, through the shank of the piston and into the cylinder. The cylinder then moves back and contacts the bolt carrier transferring energy to the bolt carrier. The bolt carrier then moves back causing the bolt to rotate, disengaging the bolt lugs from the barrel extension. Then the bolt carrier and bolt continue rearward under inertia extracting the case from the chamber, ejecting it through the left or right ejection port depending on the ejection selector setting and cocking the hammer. After the fired case has been ejected, the bolt carrier is stopped and is returned forward by the recoil spring. A cartridge is striped from the top of the magazine and chambered as the bolt returns forward. When the bolt reaches its full forward position the continued forward motion of the bolt carrier rotates the bolt, locking it into the barrel extension, making the rifle ready for the next shot. When the last round is fired from the magazine, the magazine follower engages the bolt catch and locks the bolt carrier assembly in the open position. FEATURES Beretta gas piston system The Beretta ARX100 uses a fixed piston moving cylinder gas system that was designed to need minimal maintenance. Quick change barrel The barrel of the ARX100 can be removed and installed in a few seconds without tools. 17 ARX100_Manual_ 06.25.13.indd 17 6/25/13 4:19 PM