How long does CO2 last after I puncture it?

Once punctured, a cartridge commonly loses most usable pressure within roughly 24-48 hours. If you fire and then store the launcher, expect the CO2 to be mostly empty within a couple of days. For defensive staging, rely on the pull-pierce system or replace the cartridge periodically.

Byrna CO₂ Guide: 8g Vs 12g Vs 88g Cartridges (2026)

A complete Byrna CO₂ guide — which cartridge size powers which launcher, how many shots you get, and how to store and maintain your CO₂ for reliable performance.

Byrna CO₂ cartridges power your launcher and determine how many shots you get before reloading. The three sizes — 8g, 12g, and 88g — are not interchangeable, and each model is designed for a specific size: the SD and standard CL use 8g; the LE, CL-XL, and TCR use 12g; and the Mission 4 uses 88g exclusively. Use the wrong size and it simply will not work — the cartridge will not fit or will not puncture correctly. Beyond compatibility, CO₂ performance depends on storage (a punctured cartridge leaks over a day or two), temperature (cold reduces shot capacity), and maintenance (the oiler cartridge keeps internal seals healthy). This guide breaks all of that down.

⚡ Short on Time?

Most Byrna SD and standard CL owners need 8g CO₂. The LE, CL-XL, and TCR need 12g, and the Mission 4 uses 88g exclusively. Run the included oiler cartridge every 10 standard cartridges to keep internal seals healthy. And once a cartridge is punctured, it loses usable pressure within a day or two — replace it if you are staging for home defense.

Byrna CO₂: Quick Picks

Best for SD / CL — Byrna 8g CO₂ + Oiler (10-Pack)

Powers the SD and standard CL. Includes one oiler cartridge for seal maintenance.

Best for LE / CL-XL / TCR — Byrna 12g CO₂ + Oiler (10-Pack)

Higher capacity, fewer swaps. The correct size for the LE, CL-XL, and TCR. Also includes an oiler cartridge.

Best for Mission 4 — Byrna 88g CO₂ Cylinders

Extended capacity for the Mission 4 rifle — its exclusive CO₂ size. Generally sold through Byrna directly.

ℹ️ How We Researched This

We compiled Byrna‘s official CO₂ specifications, verified compatibility against manufacturer documentation and current retailer listings, reviewed shot-capacity figures from Byrna‘s product pages, and weighed user feedback on CO₂ performance across temperature ranges. Where figures varied across sources, we used Byrna‘s published numbers as the baseline and noted meaningful discrepancies.

⚠️ Critical: CO₂ Sizes Are Not Interchangeable

The SD and standard CL use 8g. The LE, CL-XL, and TCR use 12g. The Mission 4 uses 88g exclusively. Using the wrong size will not work — the cartridge will not fit or will not puncture correctly. One thing that surprises buyers: even within the compact .61 family, the standard CL uses 8g while the larger CL-XL uses 12g. Always verify which size your launcher requires before ordering.

Red Flags: Byrna CO₂ Mistakes to Avoid

Using the wrong cartridge size. 8g (SD, standard CL) and 12g (LE, CL-XL, TCR) are not interchangeable. The wrong size will not fit or will not puncture properly.
Leaving punctured CO₂ in your launcher for weeks. Once punctured, a cartridge leaks over roughly a day or two. If you fire once and then store the launcher for defense, that CO₂ will likely be empty when you need it.
Skipping the oiler cartridge. Each 10-pack includes one oiler cartridge. Running it roughly every 10 standard cartridges lubricates the internal seals; skipping it can lead to dry seals, velocity drops, and misfires over time.
Using off-brand CO₂. Byrna warns that some off-brand cartridges may not puncture correctly, and users commonly report issues with certain generic 12g cartridges. Using non-conforming CO₂ can also affect your warranty — stick with Byrna-spec cartridges.
Storing CO₂ in extreme temperatures. Unpunctured CO₂ keeps for years at room temperature, but hot cars or freezing garages can affect performance or seals. Aim for a cool, dry spot rather than a vehicle or unheated garage.
Expecting full shot capacity in the cold. CO₂ pressure drops in cold weather, so expect noticeably fewer shots and lower velocity below freezing. Plan around it if you carry in winter.
Not knowing when to replace CO₂. If velocity drops noticeably or projectiles fire weakly, the cartridge is depleted — replace it rather than assuming there are “a few shots left.”

Byrna CO₂ Compatibility Chart

Byrna Model	CO₂ Size	Approx. Shots per Cartridge
Byrna SD	8g	Commonly ~20–22
Byrna CL	8g	Commonly ~15
Byrna CL-XL	12g	Commonly ~17
Byrna LE	12g	Commonly ~17–20
Byrna TCR	12g	Commonly ~20–25
Byrna Mission 4	88g only	Commonly ~55–60

Shot counts are commonly reported figures at room temperature (around 70°F); cold reduces capacity. The Mission 4 operates exclusively on 88g — 12g and 8g cartridges are not compatible. Note that the standard CL and CL-XL share the .61 ammo line but use different CO₂ sizes (8g vs 12g).

8g vs 12g vs 88g: What’s the Difference?

8g CO₂ Cartridges (SD and Standard CL)

The smallest size Byrna uses — compact and lightweight, designed for pistol-sized launchers with limited internal space. The SD and standard CL both run on 8g. The SD commonly gets around 20–22 shots per cartridge; the CL commonly gets around 15, because its higher rated velocity and design use more gas per shot. The upside of 8g is size and availability; the tradeoff is lower shot capacity than 12g, and 8g is not compatible with the LE, CL-XL, TCR, or Mission 4. Pick up the 8g CO₂ + Oiler 10-pack for these launchers.

12g CO₂ Cartridges (LE, CL-XL, and TCR)

The mid-size option, holding more gas than 8g for more shots per reload. The LE, the CL-XL, and the TCR all use 12g as standard. The LE commonly gets around 17–20 shots; the TCR rifle platform commonly gets around 20–25. The 12g cartridge is also a widely stocked size because it is common in the paintball and airsoft world, so resupply tends to be easier. The main tradeoff is that 12g will not fit the SD or standard CL. Grab the 12g CO₂ + Oiler 10-pack for these launchers.

88g CO₂ Cylinders (Mission 4)

The largest size, used by the Mission 4 rifle. An 88g cylinder delivers far more shots before replacement — Byrna lists roughly 55–60 rounds — which dramatically cuts reload frequency during extended sessions and is convenient for defensive staging. The tradeoffs are that 88g fits only the Mission 4, is physically much larger, and is less common in retail than 8g or 12g. The 88g cylinder is generally sold through Byrna directly. The Mission 4 operates exclusively on the 88g system — it will not accept 12g or 8g cartridges.

How Many Shots Per CO₂ Cartridge?

Shot capacity depends on cartridge size, launcher velocity, and temperature. Commonly reported figures at room temperature:

Launcher	CO₂	Commonly Reported Shots
Byrna SD	8g	~20–22
Byrna CL	8g	~15
Byrna CL-XL	12g	~17
Byrna LE	12g	~17–20
Byrna TCR	12g	~20–25
Byrna Mission 4	88g	~55–60

Why counts vary: cartridge size sets the ceiling, but launcher design and how much gas each shot uses matter too. The CL typically gets fewer shots than the SD despite sharing the same 8g cartridge, because its design prioritizes higher velocity and uses more gas per shot. Temperature matters as well — cold weather can cut shot capacity substantially.

💡 Pro Tip

Byrna lists shot capacity at room temperature (around 70°F). In cold weather (below roughly 40°F), expect noticeably fewer shots per cartridge because CO₂ pressure drops as temperature falls. If you carry in winter, keeping a spare cartridge in an inside pocket close to body heat can help maintain more consistent performance.

The Oiler Cartridge: Why It Matters

Every Byrna CO₂ 10-pack includes one oiler cartridge, identifiable by its black tip or label. It is not a standard CO₂ cartridge — it contains a small amount of lubricant that maintains your launcher’s internal seals as you fire.

The routine is simple: run nine standard cartridges normally, then install the oiler cartridge as your tenth and fire it normally so the oil disperses through the system. After that, your seals are lubricated, and you repeat the cycle every 10 cartridges. Skip it over time and the internal seals dry out, which leads to velocity drops, inconsistent firing, gas leaks, and eventually failure to puncture or fire. One caution: the oiler cartridge is a maintenance item, not a defensive load — use it during practice, then load a fresh standard cartridge for home defense or carry. A standalone oiler is sometimes available through Byrna directly if you run out before finishing a pack.

CO₂ Storage and Shelf Life

Unpunctured cartridges have a very long shelf life when stored properly — the sealed gas won’t escape unless the cartridge is damaged or punctured. The gas is sealed inside and will not leak unless the cartridge is damaged or punctured. Keep them in a cool, dry location (roughly 50–80°F is ideal), away from extreme heat like a summer car or direct sunlight, and away from extreme cold like an unheated winter garage. Leaving them in original packaging until use is fine.

Punctured cartridges are a different story. Once you pull the trigger and puncture the cartridge, the gas begins leaking and commonly loses most usable pressure within roughly 24–48 hours. If you fire a test shot and then store the launcher for home defense, that CO₂ will likely be mostly empty within a couple of days. This is why Byrna CO₂ replacement is part of normal ownership rather than a rare event — staged cartridges should be rotated on a schedule, not left indefinitely.

ℹ️ Home-Defense Staging Rule

If you keep a Byrna loaded for defensive use, take advantage of Byrna‘s pull-pierce design: the cartridge stays unpunctured until the first trigger pull, so you can store the launcher with CO₂ installed and it only punctures when you fire. If a cartridge has already been punctured, replace it — and as general practice, swap the staged cartridge every few months to ensure full pressure when it matters.

Temperature Effects on CO₂ Performance

CO₂ is temperature-sensitive: pressure rises with heat and falls with cold, and the sweet spot is roughly 60–80°F. At room temperature you will see the full shot capacity Byrna lists.

In cold weather (below roughly 40°F), expect noticeably fewer shots and lower velocity, and the cartridge may not fully deplete before performance degrades. Keeping spare cartridges warm in an inside pocket helps. In hot weather (above roughly 90°F), increased pressure can raise velocity, and storing cartridges in extreme heat — like a car cabin that reaches well over 100°F — risks over-pressurization. Avoid leaving CO₂ in a hot vehicle for extended periods.

⚠️ Reality Check

If you carry your Byrna in a vehicle year-round, CO₂ performance will fluctuate with the seasons — fewer shots in winter, over-pressurization risk in summer. The practical fix is to keep the launcher in climate-controlled spaces when you can, and rotate CO₂ cartridges seasonally rather than letting them bake or freeze in the car for months.

Byrna Boost Adapter: Using 12g in Some 8g Models

Byrna has offered a Boost adapter that lets certain 8g models (such as the SD, EP, and HD) accept 12g cartridges instead, increasing shot capacity by roughly 50% — an SD that gets around 20–22 shots on 8g can get closer to 30 on 12g via the adapter. The tradeoffs are that the adapter requires installation rather than being plug-and-play, adds some bulk, and uses the slightly larger 12g cartridge. Availability and model compatibility change over time, so check Byrna‘s current lineup for which launchers a Boost-style adapter supports before buying. For many owners, simply carrying a spare 8g cartridge is simpler than adding an adapter — but if you want more capacity without stepping up to an LE or rifle, it is an option worth knowing about. Browse current options through Byrna’s lineup.

Questions People Ask About Byrna CO₂

Which CO₂ size does my Byrna use?

The SD and standard CL use 8g. The LE, CL-XL, and TCR use 12g. The Mission 4 uses 88g exclusively. Check your launcher’s manual or product page to confirm before ordering.

How many shots do I get per CO₂ cartridge?

Commonly reported room-temperature figures: SD (8g) ~20–22, CL (8g) ~15, CL-XL (12g) ~17, LE (12g) ~17–20, TCR (12g) ~20–25, Mission 4 (88g) ~55–60. Cold weather can reduce these counts substantially.

If I only fire a few shots in my TCR, how do I empty the rest of the CO₂?

Once the cartridge is punctured, Byrna recommends emptying the remaining gas before removing it. The normal process is to remove the magazine and projectiles first, then point the launcher in a safe direction and continue firing until the CO₂ is fully depleted. Once there is no pressure left, open the CO₂ access door and remove the empty cartridge. Keep hands away from escaping CO₂, since it gets extremely cold. If the launcher will not fire but still has a punctured cartridge inside, follow Byrna‘s pressure-release procedure in the manual or contact Byrna support directly.

Can I use regular paintball CO₂ in my Byrna?

Byrna recommends its own cartridges because they are tested for proper puncture and performance, and it warns that some off-brand cartridges may not puncture correctly. Using non-conforming CO₂ can also affect your warranty. When in doubt, stick with Byrna-spec cartridges.

How long does CO₂ last after I puncture it?

Once punctured, a cartridge commonly loses most usable pressure within roughly 24–48 hours. If you fire and then store the launcher, expect the CO₂ to be mostly empty within a couple of days. For defensive staging, rely on the pull-pierce system (which keeps CO₂ unpunctured until the first trigger pull) or replace the cartridge periodically.

How often should I do a Byrna CO₂ replacement?

For a launcher you stage for home defense, a good rule is to replace the CO₂ every few months even if it has not been punctured, so you always have full pressure. If a cartridge has already been punctured, replace it right away rather than relying on the leftover gas. For range and practice use, simply replace the cartridge whenever velocity drops or projectiles start firing weakly.

What is the oiler cartridge, and do I really need it?

The oiler cartridge (included in every 10-pack) lubricates your launcher’s internal seals. Running it roughly every 10 standard cartridges helps prevent dry seals, velocity drops, and misfires. Skipping it tends to cause performance problems over time.

Can I store CO₂ cartridges in my car?

Not ideal for long-term storage. Cars reach extreme temperatures in summer and winter, which can affect performance or seals. Store unpunctured cartridges in a cool, dry place around 50–80°F. Carrying CO₂ in the vehicle short-term is fine; leaving it there for weeks in extreme heat or cold is not.

Can I use 12g CO₂ in my SD or CL?

Not without modification. The SD can use 12g with a Byrna Boost-style adapter installed. The standard CL is built around 8g. The LE, CL-XL, and TCR require 12g and cannot use 8g. Always use the correct size for your launcher, or the manufacturer-approved adapter where one exists.

Final Thoughts: Byrna CO₂ Best Practices

Byrna CO₂ comes down to a few simple habits: use the right size for your launcher, run the oiler cartridge every 10 rounds, and replace punctured cartridges if you are staging for defense. The most common mistake is leaving a punctured cartridge in the launcher for weeks and expecting it to work — it will not, because CO₂ loses usable pressure within a day or two of being punctured.

If you carry or stage a Byrna for self-defense, either keep it loaded with an unpunctured cartridge (using the pull-pierce system) or build Byrna CO₂ replacement into your routine every few months. Temperature matters too — cold cuts shot capacity, and extreme heat can over-pressurize — so store spares at room temperature and carry extras if you use your launcher in harsh conditions. Match the cartridge to the model: 8g for the SD and standard CL, 12g for the LE, CL-XL, and TCR, and 88g for the Mission 4.

For help choosing a launcher and understanding how CO₂ capacity factors into defensive performance, see our complete Byrna guide and the individual model reviews.