GO2 Weapons MK18 Piston is the newest version from our Close Quarters Battle Rifle lineup. Chambered in 5.56 NATO along with its proven 3 position piston reliability and compact frame makes it the Ultimate CQB platform. The match grade 11." SEPR barrel enhances the weapons accuracy when the operator is forced to engage targets at longer distances. The barrel's special profile allows for longer full auto run time if required. The MK18 utilizes a combat trigger that provides the shooter with a crisp, clean trigger pull for ultimate control. The GO2 MK18 piston was designed from the ground up with close quarter battle in mind