Airsoft Gas Blowback 101- How Does a GBB Work?

Summary

This video provides a detailed explanation of how gas blowback airsoft guns function. It covers the operation of the magazine, the role of the gas reservoir and valves, the mechanics of the fire control group, and the nozzle's function during blowback. The script also discusses the differences between rifles and pistols, explaining the processes of semi-auto and full-auto firing, as well as the stop-on-empty mechanisms. In essence, it demystifies the inner workings of airsoft guns and highlights common myths and troubleshooting tips, making it easier for enthusiasts to maintain and upgrade their guns.

Takeaways

• 😀 Gas blowback airsoft guns function similarly across models, with minor variations, making understanding the core system useful for troubleshooting and upgrades.
• 😀 The magazine in a gas blowback gun consists of a BB feed track and a gas reservoir, with various configurations for different designs, but all serving the same fundamental purpose.
• 😀 Green gas, typically propane with added silicone oil, is the common power source for most airsoft guns, although some prefer oil-free gas or hardware store propane with an adapter.
• 😀 Gas magazines operate under vapor pressure, which fluctuates based on the amount of liquid and gas inside, and the temperature affects this process.
• 😀 The fill valve in a magazine is used to fill it with propellant, and on some designs, the two-way valve releases gaseous propane until the magazine is full.
• 😀 The output valve releases gas when struck by the hammer, allowing the gas to enter the gun, but tilting the magazine improperly can release liquid propane, which is undesirable.
• 😀 The fire control group uses a hammer or striker to release the valve knocker, which allows gas to flow from the magazine, thus driving the gun's recoil mechanism.
• 😀 Some guns include a valve knocker lock to maintain gas flow until triggered later in the blowback cycle, improving recoil and functioning at lower gas pressures.
• 😀 Nozzles have a rocket valve that controls gas release, and as pressure builds, the nozzle functions as a piston to drive the slide or carrier back during blowback.
• 😀 On most guns, the hammer or striker resets with the slide movement, and a disconnector ensures semi-auto firing, while full-auto guns bypass the disconnector for continuous fire.
• 😀 When the magazine is empty, the stop-on-empty system engages to lock the slide or carrier back, signaling the user that the magazine needs to be replaced or reloaded.

Q & A

What is the fundamental working principle behind most modern gas blowback airsoft guns?

Most modern gas blowback airsoft guns work fundamentally the same way with only minor variations. The essential process involves the use of a gas-powered magazine that releases gas into the gun's internals to propel the BB and cycle the mechanism.

How does a gas blowback airsoft magazine work?

A gas blowback airsoft magazine consists of a BB feed track and a gas reservoir. The BB feed track delivers BBs to the gun's chamber, while the gas reservoir holds the propellant. When the gun is fired, a valve releases gas from the reservoir, cycling the mechanism.

What is the role of the feed lips in a gas blowback airsoft magazine?

The feed lips in a gas blowback airsoft magazine prevent BBs from falling out of the top while allowing them to push out the front and feed into the gun's chamber.

Why is green gas commonly used as a propellant for gas blowback airsoft guns?

Green gas, typically propane with added silicone oil, is the most common propellant for gas blowback airsoft guns because it provides consistent pressure and reliable function. However, propane without the odorant can also be used with a fill adapter.

What is vapor pressure, and why is it important for gas blowback airsoft guns?

Vapor pressure refers to the pressure at which liquid and gas are in equilibrium. It is crucial for maintaining consistent pressure in the magazine and gun. The gas will continue to expand into vapor as long as the pressure inside the reservoir is below vapor pressure.

What is the role of the valve knocker in a gas blowback airsoft gun?

The valve knocker is a key component in the fire control system. When the trigger is pulled, the hammer releases and pushes the valve knocker forward, opening the magazine's gas valve and releasing propellant to cycle the gun.

How does the blowback action in airsoft guns generate recoil?

The blowback action generates recoil by using the pressure of the gas to push the nozzle and carrier/slide backwards. This movement is what resets the hammer and generates the felt recoil in the user's hand.

What happens to the gas inside the nozzle after the airsoft gun is fired?

Once the gas is released into the nozzle, it builds pressure, pushing the nozzle forwards. This pressure pushes the slide or carrier backward, and as the nozzle depressurizes, the cycle continues until the magazine is empty.

What function does the disconnector serve in gas blowback rifles and pistols?

The disconnector temporarily disengages the trigger from the hammer mechanism, ensuring the gun cycles correctly in semi-auto mode. This allows the hammer to be reset by the slide or carrier without immediately triggering the next shot.

What is the purpose of the stop-on-empty system in gas blowback guns?

The stop-on-empty system prevents the gun from firing once the magazine is empty. It activates when the magazine follower pushes up on the slide catch or bolt catch, which holds the slide or carrier in the rear position, signaling the shooter that the magazine is out of ammo.