Daisy BB Guns, Crosman BB Guns
BB Guns and BB Gun Kits By:
Daisy, Cosman, Gamo and Walther.
How do BB guns work?
The principle behind BB guns is pretty much the same as in firearms, except there is no explosion. The expanding matter is ordinary air, carbon dioxide or some other gas. Before you fire the BB guns, the gas is compressed so that it has a greater density, and consequently a greater pressure than the air in the atmosphere outside the gun. The compressed gas is stored in an airtight container until you pull the trigger. This opens up the gas container so the gas can flow out into the barrel of the gun, just behind the BB. Since it is more compressed, the gas behind the BB pushes out with greater force than the air in the atmosphere pushes in, and the BB is propelled forward at great speed. This is the idea behind all gas-powered guns, including high-powered air rifles.
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There are several different air-gun designs, which differ mainly in the source of the compressed air:
- In pneumatic designs, you build up a reservoir of compressed gas by manually pumping air. The movable lever on the bottom of the BB gun moves a small piston in a tube. Inside the tube, there is a check valve that lets air flow in but not back out. In this way, each pump of the gun increases the amount of air in the reservoir, which has a set volume. Since mass is increased while volume is held constant, the density and pressure of the air increases with every pump.
- Another common system is the spring air design. In this sort of BB gun, the "pump" lever pushes back on a small piston, which compresses a spring behind it. As the piston slides back, it catches on a small, spring-driven latch that swivels on a tiny pin. This latch, commonly called a sear, holds the piston in position, so the spring stays compressed. When you pull the trigger, it pushes on the sear so it lifts off the piston. With the piston unlatched, the spring can expand out, pushing the piston forward. This quickly compresses the air in the chamber behind the BB, building up the pressure needed to propel it down the barrel.
- Some air guns don't have any sort of pump action. The gas is pre-compressed and stored in cylinders, like the air in a scuba tank. To shoot the BB, the gun mechanism just has to open the pathway between this gas source and the chamber behind the BB (or other projectile). There are many different air-gun designs that accomplish this feat.
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