Your Buying Guide to Co2 Cartridges for Airsoft & BB Guns

Whether you're powering an airsoft sidearm for skirmish day or plinking in the garden with a BB pistol, choosing the right Co2 cartridges can make a real difference to consistency, shot count, and overall enjoyment. This guide breaks down everything you need to know before hitting "add to basket" — from cartridge sizes and brand comparisons to bulk-buying tips and storage advice.

Why Buy Your 12g Co2 Cartridges From Us?

We stock one of the biggest ranges of Co2 capsules in the UK, from single cartridges right up to 500-packs — and we back every order with our Price Match Guarantee. If you find the same product cheaper at another UK retailer, we'll beat it. Orders over £75 qualify for free UK shipping, and our expert customer support team are fellow airsoft players, so we genuinely understand what you need. With over 10,000 airsoft products on site and fast UK shipping as standard, you can grab your cartridges alongside BB pellets, airsoft pistols, or any other gear in a single order.

Understanding Co2 Cartridge Sizes: 12g vs 88g

The Standard 12g Co2 Cartridge

The 12g Co2 cartridge is the workhorse of the airsoft world. It's the small, disposable capsule that slots into the grip or magazine of most Co2 pistols and revolvers. A single 12g cartridge typically delivers between 40 and 80 shots depending on the gun, temperature, and whether the pistol is blowback or non-blowback. If you own a co2 airsoft pistol — whether it's a 1911, a Glock replica, or a revolver — this is almost certainly the size you need.

The Larger 88g Co2 Capsule

88g capsules are designed primarily for Co2 air rifles and some paintball markers. They offer far more shots per capsule (often 150+), which makes them practical for longer shooting sessions without the need to swap gas mid-game. We carry options such as the ASG ULTRAIR 88g cartridge and the Umarex 88g capsule, both of which are compatible with a wide range of air rifles. If you're unsure which size your gun takes, check the manufacturer's manual or drop our support team a message.

Comparing Popular Co2 Cartridge Brands

Not all cartridges are created equal. Here's a quick rundown of the main brands we stock and what sets them apart:

ASG ULTRAIR vs Nuprol

ASG ULTRAIR cartridges are widely regarded as one of the most consistent options on the market. They're manufactured to tight tolerances, which means reliable piercing and steady gas output shot after shot. We carry ASG packs from 1 all the way up to 500, plus their handy lubrication maintenance cartridges — a clever product that deposits a small amount of silicone oil into your gun's valve and seals every time you load one, helping to extend the life of your pistol's internals.

Nuprol cartridges offer excellent value, especially in bulk. Available in packs of 25, 50, 75, 100, 200, 300, 400, and 500, they're a solid everyday choice for players who get through a lot of gas. Quality control is good, and they fit all standard 12g Co2 guns without issue.

Umarex, Cybergun & Others

Umarex Co2 cartridges come from one of the most established names in air-powered shooting sports. They're a dependable pick for both airsoft pistols and air rifles. Cybergun capsules sit at a competitive price point and are perfectly serviceable for casual plinking and garden target practice. We also stock budget-friendly options from Anglo Arms and Milbro for those who want a no-frills cartridge at the lowest cost.

Practical Buying Advice for Co2 Capsules

Buy in Bulk to Save Money

If you skirmish regularly or simply enjoy backyard shooting, buying in larger packs is by far the most cost-effective approach. A 12g Co2 cartridge 100 pack — or even a 200 or 500 pack — brings the per-unit price down significantly. Since Co2 cartridges have no expiry date when stored correctly, there's no downside to stocking up.

Storage Tips

Keep your cartridges in a cool, dry place away from direct sunlight. Avoid storing them loose where they could roll around and get dented — a damaged cartridge can fail to pierce properly or leak gas. The original box or a simple plastic container works fine.

Don't Forget Maintenance

Co2 can dry out the rubber seals inside your gun over time. Using an ASG ULTRAIR lubrication cartridge every 5–10 standard cartridges helps keep seals supple and prevents costly leaks. It's a small investment that can save you from replacing magazines or entire valve assemblies down the line.

Co2 vs Green Gas: Which Should You Choose?

This is one of the most common questions new players ask. Co2 airsoft guns generally deliver higher FPS and more consistent performance in cold weather compared to green gas models. Green gas, on the other hand, is refillable (so there's no single-use cartridge waste) and tends to be gentler on gun internals. If you play outdoors year-round in the UK, Co2 is often the better choice simply because our winters can really sap green gas performance. If you primarily play indoors or during summer, green gas is a perfectly viable alternative. Many players own guns in both platforms — it's not an either-or decision. Browse our full selection of airsoft gas options to compare.

Frequently Asked Questions

How many shots do you get from a 12g Co2 cartridge?

It varies by gun, but most Co2 pistols deliver between 40 and 80 shots per cartridge. Blowback models use more gas per shot than non-blowback versions, so expect to be at the lower end of that range with a gas blowback pistol. Cold weather also slightly reduces shot count.

Can I leave a Co2 cartridge in my gun between uses?

It's generally fine to leave a partially used cartridge in your gun for a day or two, as long as there's still some gas pressure keeping the seal engaged. However, leaving one in for weeks on end can stress the pierce pin seal and lead to slow leaks. If you're done for the day, it's better to shoot out the remaining gas and remove the spent cartridge.

Are all 12g Co2 cartridges the same size?

Yes — the 12g Co2 cartridge is an industry-standard size (roughly 83 mm long and 18 mm in diameter). Cartridges from ASG, Nuprol, Umarex, Cybergun, and other reputable brands are all interchangeable in any gun designed for 12g capsules. The differences between brands come down to manufacturing consistency and pricing rather than physical dimensions.

Is it cheaper to buy a Co2 cartridge 100 pack?

Absolutely. Bulk packs offer the best value per cartridge. For example, a 100-pack of ASG ULTRAIR or Nuprol capsules will cost considerably less per unit than buying ten individual cartridges. If you're a regular player, a 100-pack is a sensible starting point — and our 200, 300, and 500 packs push the savings even further.

Do Co2 capsules expire?

No. Sealed Co2 cartridges do not have a use-by date. As long as they are stored properly — away from moisture, extreme heat, and physical damage — they will perform just as well years from now as the day you bought them. This is another reason why buying in bulk makes perfect sense.