Electric airsoft guns that are built with a metal gearbox are far superior to that of versions using plastic gearboxes for a variety of reasons. The main advantages associated with full metal airsoft guns are increased power, an improved rate of fire and greater level of durability. Metal airsoft guns also include a more durable and stronger power unit/motor too. Plastic gears can easily be broken, warped and melted but for the most part are cheaper to produce. However, all metal airsoft guns typically shoot around 330 to 600 FPS with .20g bbs in comparison to a plastic gearbox gun that shoots a mere 140 to 300 FPS with only .12g bbs. The rate of fire (ROF) for metal airsoft rifles are typically around 900 to 1500 RPM (rounds per minute) while cheaper plastic rifles range from 150 to 400 RPM.
