Internally all RK guns features G&G's excellent and innovative gearbox that are made with the highest precision and quality that rivals competing and even higher tier guns. They are designed to be reliable and balanced, shooting in the 350 FPS range - the maximum allowed FPS for many close quartered combat scenarios in many airsoft arenas. While being housed in a full metal body which includes the receiver, receiver cover, cover retainer button, trigger, trigger guard, magazine release, magazine, bolt and charging handle, mock gas piston, fire selector lever, rear sight, gas tube release lever, hand guard retainers, front sight block, and its threaded outer barrel