Spring-powered airsoft guns are single-shot devices that use elastic potential energy (EPE) stored in a spring to compress air to launch an airsoft pellet down the barrel of the gun. It"s fast, clean, inexpensive and easily maintained, it requires no gas or batteries to operate. The user must cock a spring gun prior to each shot. This is typically achieved by pulling back the slide (pistols), bolt (rifles), or the grip on a shotgun, which in turn compresses the spring and makes the gun ready to fire. Spring Airsoft Guns are the toughest, most durable of all Airsoft Guns, because they"re made with few breakable pieces.