CO2 cartridges are the fuel that powers your pistol or rifle — and understanding them is essential to getting the most out of your shooting sessions. Here is everything you need to know.
CO2 Cartridge Sizes
12g CO2 Cartridges (Standard)
The most common type. Used in virtually all CO2 pistols and most CO2 rifles. Dimensions are standardised — if your gun takes a 12g cartridge, any brand will fit (Umarex, Walther, Crosman, etc.). The necked end is pierced by the gun's pin when installed.
- Weight: 12 grams of liquid CO2
- Typical shot count: 40–80 shots (.177 BB)
- Best for: Pistols, short sessions
88g / 90g CO2 Cartridges (Large)
Used in larger CO2 rifles and some carbines. Less common but offer significantly more shots per fill. They thread into the gun rather than being pierced.
- Weight: ~88–90 grams of liquid CO2
- Typical shot count: 400–700+ shots
- Best for: Rifles, extended range sessions
How Many Shots Will I Get?
Shot count varies based on several factors:
| Factor | Effect on Shot Count |
|---|---|
| Temperature | Cold = fewer shots (lower pressure) |
| Valve size | Larger valve = more gas per shot = fewer shots |
| Blowback action | Blowback uses ~30% more CO2 than non-blowback |
| Calibre | .22 calibre uses more gas per shot than .177 |
| Shooting pace | Rapid fire cools the cartridge, reducing pressure temporarily |
As a rough guide: a 12g cartridge in a blowback .177 BB pistol at 20°C will give you 50–65 shots before you notice a significant velocity drop.
Why Do Cartridges Frost Over?
When CO2 expands from liquid to gas, it absorbs heat from its surroundings — this is called endothermic expansion. The cartridge and the gun's CO2 housing can actually frost over during rapid fire. This is normal and not damaging, but it means your CO2 pressure has temporarily dropped. Pause for 30–60 seconds and performance will recover.
Storage Guidelines
- Temperature: Store between 10°C and 30°C. Never in a hot car, direct sunlight, or near heat sources. Above 50°C, pressure rises dangerously and cartridges can rupture.
- Humidity: Keep dry. Moisture causes surface rust on steel cartridges, which can jam the gun's piercing pin or cause valve contamination.
- Long-term storage: Do not leave a cartridge installed in your gun for more than 48 hours. Even "sealed" valves leak slowly over time, and the residual CO2 can damage rubber o-rings.
- Children: Treat CO2 cartridges like compressed gas cylinders — keep away from children.
Shelf Life
Unopened, sealed CO2 cartridges stored correctly have an effective shelf life of 5–10 years. The seal foil at the neck degrades slowly over time, so very old stock may show slightly reduced shot counts. Buy from reputable sources to ensure you are getting fresh stock.
Safe Disposal
- Always fully depressurise cartridges before disposal — install and fire until no gas remains, or pierce with a dedicated depressuriser tool
- Once empty, CO2 cartridges can be disposed of with general metal recycling
- Never puncture a full or partially-full cartridge with a sharp tool
Which Brand Should I Buy?
For 12g cartridges, all major brands (Umarex, Walther, Crosman, Air Arms) are essentially equivalent in CO2 content and seal quality. We stock Umarex 12g cartridges — sold individually, in packs of 5, 10, and 25 for savings on larger quantities.
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