# CO2 cartridge

12 gram **CO _{2} cartridges** are used primarily as a portable way to provide pressurized gas to a pneumatic cannon. They cost roughly $0.50 a piece, and are typically connected via an adapter, which can be purchased for about $10 USD.
Once empty, they are often used as projectiles - they have a high mass, are quite sturdy, and fit in 3/4" SCH. 40 PVC.

The following is a chart outlining the chamber size (in cubic inches) vs. pressure in (pounds per square inch) using a 12 gram CO2 cartridge:

Chamber Size (ci) | Chamber Pressure (PSI) |

10 | 420 |

20 | 210 |

30 | 140 |

40 | 105 |

50 | 84 |

60 | 70 |

70 | 60 |

80 | 53 |

90 | 47 |

100 | 42 |

To calculate the pressure for any non-given value, use this equation, but note that the pressure can't go above 800 PSI (the vapor pressure of CO2).

4200/Chamber Volume In ci=Chamber Pressure in psi -OR- 4200/CV=CP

For example:

You have a chamber volume of 41.3ci.

So it can be said that 4200/41.3=CP

4200/41.3 is equal to 101.6949152542373 For simplicity's sake we will round this to 101.7

This means that CP=101.7 PSI

Your 41.3ci chamber will have a pressure of 101.7 PSI when filled with one 12g CO2 cartridge.