Not exactly an airsoft rifle, but it's interesting to learn more about training rifles, such as this Umarex T4E TM4 CO2-powered Training Rifle that is available at AirRattle... "The T4E TM4 is a new MilSim training weapon brought to you by Umarex. The T4E operates off of C02 cartridges that are put into the magazine, and you are capable of getting 30-40 rounds out of one capsule.