If you've ever shot or used an electric airsoft gun then you know they are pretty amazing. These detailed Milsim (Military Simulation) firearms are capable of shooting airsoft ammo accurately 100 meters or more. But exactly how do they work and what is the science behind the operation of Airsoft Electric Guns? Airsoft Guns come in Electric, Gas, and spring powered versions. For the purposes of this article we are limiting our discussion to Electric Airsoft Guns. Although some of the concepts here apply to all types of airsoft guns.

Airsoft Electric Guns (AEG) use NiCad or NiMh Rechargeable batteries to power an electric motor, which turns a gear box that compresses a spring. At the end of the cycle the spring tension is released and the piston head drives forward, propelling a plastic airsoft BB through the hop-up chamber and out of the barrel. Using this common technology, electric airsoft guns can achieve muzzle speeds between 150 and 500 FPS (Feet Per Second). Electric airsoft guns typically operate in semi-automatic and fully-automatic modes. Full-auto airsoft guns can fire at a cyclic rate of 150 to 2000 RPM, depending on the model. Gear boxes are typically made of plastic or metal. Better durability and faster rates of fire are achieved with metal gearboxes. Manufacturers have also reinforced their gearboxes to give them greater durability.

One drawback to airsoft guns is the use of smooth barrels. In a real firearm, the barrel is rifled or grooved to put spin on the bullet. This spin helps maintain a stable trajectory; like the spin on a football. Airsoft Gun barrels do not create the stabilizing spin of their real steel counterparts and the BBs move at slower rates of speed. Because of this, the airsoft BB has a natural tendency to arc downwards due to equal air pressure on the top and bottom of the BB. Those equal air pressure forces cancel each other out and the BB quickly falls to earth due to gravity. Hop up counteracts the force of gravity. Basically, the hop up chamber has a rubber wheel that grips the top of the airsoft BB as it passes through, imparting back spin on the BB. Similar to an airplane wing, the spinning BB now has different levels of air pressure on the top and bottom. The result is the principal of lift. The airsoft BB stays aloft until the spin energy dissipates, the BB looses lift, and gravity pulls the airsoft round to earth.

All of the above factors impart how much distance and how accurate your airsoft gun is going to be. Spring tension, and motor torque impart energy on the BB that will move it at a certain speed, and Hop-up ensures the BB has enough loft to carry it longer distances. The whole time your BB is working against Gravity (downward pull) and air resistance (forward resistance). 6mm Airsoft BBs come in weights of .12g, .20g, .23g, .25g, .28g, .30g, and heavier. Heavier BBs are able to better counteract wind resistance, and increase accuracy at further distances. However, because more energy is required to propel the heavier airsoft ammo forward, you loose muzzle velocity, and your range will be diminished. It's a trade-up best determined by testing various BB weights in your gun. With trying out different weights, you can determine which BB weight gives you the best combination of distance and accuracy for that particular gun.