CO2 can be divided into food-grade CO2 and industrial-grade CO2 according to the purpose. Food-grade CO2 gas purity is 99.999%, which is used to make soda water and beer. Industrial grade CO2 is usually 99% pure and is used for bicycle inflation, or airguns.
Since CO2 cools as it is used up, the CO2 tank will also become cold as you shoot and as discussed already a cold CO2 tank is less efficient. Smaller CO2 tanks will cool down much faster than larger CO2 tanks so when shooting rapped fire with a 12 gram CO2 cartridge you may only expect to get about 20-30 good shots before taking a break and letting your gun and the CO2 tank warm up again. Some CO2 airguns use 88-90 gram CO2 tanks which allow for a lot more rapid fire shots before having to allow for warmup time. Even a dual 12 gram CO2 airgun will operate better when shooting rapped fire than a single 12 gram CO2 airgun since it has double the CO2 capacity.
On pretty much all CO2 airguns there is a valve setup that when the hammer is dropped the valve is opened for a very short period of time allowing the CO2 to escape from the CO2 cartridge and enter the breach and barrel area of the gun propelling the BB, Pellet or Airsoft round. How long this valve is open for will determine how much power the gun will have and also how much CO2 is used up for each shot. More CO2 released by the valve equals more power and less shots per CO2 cartridge, less CO2 released by the valve equals less power and more shots per CO2 cartridge.
How to use airgun?
- Check the firing chamber of the airgun, making sure that it is empty and the gun is unloaded. Place the safety of the airgun on to prevent firing.
- Remove the grip panel from the CO2 airgun or loosen and remove the large screw on the bottom of the grip by turning to the left to loosen and remove.
- Insert an 8gram or 12grame CO2 cartridge into the handle of the airgun and tighten the screw so the cartridge is held in place. Do not tighten the screw to the point of puncturing the tip of the cartridge at this point.
- Load into the gun based on the particular model. Pull back the loading spring, for example, on some models so that airgun ammunition can be loaded.
- Point the CO2 airgun in a safe direction and tighten the screw on the base of the grip to puncture the CO2 cartridge.