The guns used in airsoft are typically replicas of real firearms that compress air by a variety of means to fire a lightweight plastic pellet. Airsoft guns can be loosely divided into three types based on the method used to generate the required pressure: spring powered, electric powered, and gas-powered. Firing lightweight plastic pellets at moderate velocities, airsoft is a fairly safe military style game when appropriate precautions are observed. The minimum safe level of personal protective gear required to participate in most games is a pair of impact-rated goggles to protect the eyes of the participants. Even where this requirement is not enforced, it is almost universally considered extremely foolish and needlessly dangerous to play without this minimum level of protective gear.

Spring-powered guns are manually cocked by the user, which compresses a spring inside a piston, which will make an airtight seal against its chamber when released. Once cocked, the piston is then held in place by a sear until released by pulling the trigger of the replica. The trigger releases the sear, which releases the piston, which is in turn pushed back into its original position by the action of the spring. The airtight seal of the piston against the chamber wall creates a high-pressure area behind the pellet, projecting it down the barrel and towards the intended target. Spring guns are often the cheapest of airsoft guns, as they have a minimum of internal parts. In competition play, the most popular form of spring guns are replicas of various bolt-action rifles, as the manual cocking of the spring mimics the action of the bolt on a real sniper rifle. Spring pistols must be cocked by pulling the full top portion of the gun back, while rifles usually have a lever of some sort to pull.

This a spring powered rifle Mp5

Electric airsoft guns (generally known as an "AEG" for Automatic Electric Gun) are the most commonly used type of replica found at airsoft skirmishes. The AEG gearbox utilizes the same principle as a spring gun to propel a BB, but the cocking action is automated through the use of an electric motor (similar to those found in remote control cars) used to drive a gearbox assembly that is capable of fully automatic fire at rates equivalent to those of the real automatic weapons the airsoft gun is a replica of. AEGs are typically powered by rechargeable battery packs, composed of 7-8 cells similar to those found in remote control cars.

This is a fully atomatic G-36 that is sileneced

Gas-powered guns operate by storing a pressurized gas in a liquid form (similar to storage of propane, butane, or carbon dioxide as a pressurized liquid) inside a chamber, and releasing a small amount of the liquified gas into the firing chamber (where it expands dramatically in volume) in order to propel the pellet, and usually (but not always) some of the gas is also used in "blowback" operation in order to cycle the internal mechanism and reset for the next shot. Gas-powered pistol replicas that also "blowback" the slide similar to a real pistol are typically more expensive than "non-blowback" replicas that don't do this, due to the complexity of the blowback action. Pistols are the most common form of gas blowback guns, as the blowback creates very realistic slide action on the gun. Early airsoft rifles were gas (typically CO2) powered as well, but nearly all modern rifles are of the electric type.

This is a Green gas powered airsoft gun pistol

Each of the three types of airsoft replicas has an aftermarket for upgraded internal (performance and durability) and external (cosmetic and ergonomic) parts, and many serious players upgrade their guns with parts (which may collectively cost as much or more than the original purchase of the gun in it's stock form) for a variety of reasons ranging from personal aesthetic preference to increased reliability/durability to increased accuracy/performance of their airsoft replica on the field in competition/recreation.