Airsoftjunkiez demo their Custom Stoner M63A1 HPA LMG equipped with the PolarStar F2 HPA Engine. This is made of heavy duty steel & aluminium construction with a 20mm rail on top of feed cover allows for easy mounting of optics. The railed handguard allows for easy mounting of tactical accessories and the reinforced metal gearbox w/ steel gears, spring guide, and 8mm bearings.