Byrna CO₂ Guide: 8g vs 12g vs 88g Cartridges

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. Each Byrna model is designed for a specific CO₂ size: the SD and CL use 8g cartridges, the LE and TCR use 12g, and the Mission 4 uses 88g (or 12g in some configurations). Using the wrong size won’t work—the cartridge won’t fit or won’t puncture correctly.

Beyond compatibility, CO₂ performance depends on storage (punctured cartridges leak over 24-48 hours), temperature (cold reduces shot capacity), and maintenance (oiler cartridges every 10 uses prevent seal wear). This guide breaks down which CO₂ size works with which launcher, how many shots you get per cartridge, and how to store and maintain your CO₂ system for reliable defensive performance.

Byrna CO₂: Quick Picks

Best for SD/CL: Byrna 8g CO₂ + Oiler (10-Pack) – Powers SD and CL, includes 1 oiler cartridge.
Best for LE/TCR: Byrna 12g CO₂ + Oiler (10-Pack) – Higher capacity for LE and TCR, includes one oiler cartridge.
Best for Mission 4: Byrna 88g CO₂ Cartridges – Extended capacity for Mission 4 rifle (verify your configuration)
Best Maintenance Tool: Byrna Oiler Cartridge (Single) – Lubricates internal seals, use every 10 CO₂ cartridges.
Budget Cartridges: CXWXC 88g CO₂ Cartridges – Cost less than the Byrna 88g cartridges and can be used if you want to save $$.

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Red Flags: Byrna CO₂ Mistakes to Avoid

Byrna CO₂ Compatibility Chart

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

8g CO₂ Cartridges (for SD and CL)

Compatible with: Byrna SD, Byrna CL, older Byrna HD/EP models

8g CO₂ cartridges are the smallest size Byrna uses. They’re compact, lightweight, and designed for pistol-sized launchers where space is limited. The Byrna SD and Byrna CL both use 8g cartridges.

Shot capacity:

• SD: 20-22 shots at 280-300 FPS
• CL: ~15 shots at 400 FPS (higher velocity uses more gas per shot)

Advantages:

• Compact size fits pistol grip frames
• Lighter weight (less launcher bulk)
• Widely available online and in stores

Disadvantages:

• Lower shot capacity compared to 12g
• Not compatible with LE, TCR, or Mission 4

Where to buy: Byrna 8g CO₂ + Oiler 10-Pack on Amazon

12g CO₂ Cartridges (for LE and TCR)

Compatible with: Byrna LE, Byrna TCR, Byrna SDXL/HDXL, Mission 4 (some configurations), SD/HD with Byrna Boost adapter

12g CO₂ cartridges are the mid-size option. They hold 50% more gas than 8g cartridges, providing more shots per reload. The Byrna LE and TCR use 12g cartridges as standard.

Shot capacity:

• LE: 17-20 shots at 330 FPS
• TCR: 20-25 shots (rifle platform, more efficient gas usage)

Advantages:

• Higher shot capacity than 8g
• More widely available than 88g (paintball/airsoft standard size)
• Can be used with the Boost adapter on SD/HD for increased capacity

Disadvantages:

• Won’t fit in SD or CL without adapter modification
• Slightly larger/heavier than 8g

Where to buy: Byrna 12g CO₂ + Oiler 10-Pack on Amazon

88g CO₂ Cartridges (for Mission 4)

Compatible with: Byrna Mission 4 rifle

88g CO₂ cartridges are the largest size Byrna uses. They’re exclusive to the Mission 4 rifle platform and provide significantly extended shot capacity compared to pistol cartridges.

Shot capacity:

• Mission 4: 55-60 shots per 88g cartridge

Advantages:

• Massive shot capacity (3-4x more than 12g)
• Reduces reload frequency during extended sessions
• Better for home defense staging (more shots available immediately)

Disadvantages:

• Only compatible with Mission 4
• Larger physical size (won’t fit pistol platforms)
• Less common in retail stores compared to 8g/12g

Note: Mission 4 is designed around the 88g system. Confirm your specific configuration before purchasing CO₂ cartridges.

How Many Shots Per CO₂ Cartridge?

Shot capacity varies based on CO₂ size, launcher velocity, and temperature:

8g cartridges:

• Byrna SD (280-300 FPS): 20-22 shots
• Byrna CL (400 FPS): ~15 shots

12g cartridges:

• Byrna LE (330 FPS): 17-20 shots
• Byrna TCR (rifle platform): 20-25 shots

88g cartridges:

• Byrna Mission 4: 55-60 shots

Why shot counts vary: Higher velocity uses more CO₂ per shot. The CL fires at 400 FPS (same as LE) but uses 8g CO₂, so it gets fewer shots (15) compared to the SD’s 20-22 shots at lower velocity. Temperature also affects performance—cold weather can reduce shot capacity by up to ~30-40%.

The Oiler Cartridge: Why It Matters

Every Byrna CO₂ 10-pack includes 1 oiler cartridge (identifiable by the black tip or label). This isn’t a regular CO₂ cartridge—it contains a small amount of lubricant that maintains your launcher’s internal seals as you fire.

How to use the oiler cartridge:

1. Use 9 standard CO₂ cartridges normally
2. On the 10th cartridge, install the oiler cartridge
3. Fire normally—the oil disperses through the system as you shoot
4. After finishing that CO₂, your launcher’s seals are lubricated
5. Repeat every 10 cartridges

What happens if you skip it: Over time, internal seals dry out. This causes velocity drops, inconsistent firing, gas leaks, and eventually complete failure to puncture or fire. The oiler cartridge helps prevent these issues by keeping seals pliable and properly lubricated.

Don’t use the oiler cartridge for defensive staging: The oiler cartridge is for maintenance, not defense. Use it during practice/training sessions, then load a fresh standard CO₂ cartridge for home defense or carry.

CO₂ Storage and Shelf Life

Unpunctured CO₂ Cartridges

Shelf life: Indefinite when stored properly

Unpunctured CO₂ cartridges have virtually unlimited shelf life. The gas is sealed inside and won’t leak as long as the cartridge isn’t damaged or punctured.

Storage conditions:

• Cool, dry location (50-80°F ideal)
• Avoid extreme heat (cars in summer, direct sunlight)
• Avoid extreme cold (unheated garages in winter)
• Keep in original packaging until use

Punctured CO₂ Cartridges

Usable time after puncture: Typically 24-48 hours

Once you pull the trigger and puncture the CO₂ cartridge, gas typically begins leaking and may lose most usable pressure within 24-48 hours. If you fire your launcher once for a test and then store it for home defense, that CO₂ is likely empty when you need it.

Home defense staging rule: If you’re keeping your Byrna loaded for defensive use, replace the CO₂ cartridge every 2-3 months, even if you haven’t fired it. This ensures full pressure when you need it. Better yet, keep an unpunctured CO₂ installed and only puncture it when you need to fire.

Byrna’s pull-pierce technology keeps the CO₂ unpunctured until the first trigger pull. This means you can store your launcher with CO₂ installed indefinitely—it only punctures when you fire.

Temperature Effects on CO₂ Performance

CO₂ is temperature-sensitive. Gas pressure increases with heat and decreases with cold.

Optimal temperature range: 60-80°F

At room temperature, CO₂ performs as advertised. You’ll get the full shot capacity listed by Byrna.

Cold weather (below 40°F):

• Expect up to ~30-40% reduced shot capacity
• Velocity drops (lower FPS)
• CO₂ may not fully empty the cartridge before performance degrades
• Keep spare cartridges warm in the inside pockets

Hot weather (above 90°F):

• Increased pressure can cause higher velocity (sometimes beyond spec)
• Risk of over-pressurization if cartridges are stored in extreme heat (120°F+ in cars)
• Don’t leave CO₂ cartridges in hot vehicles for extended periods

Byrna Boost Adapter: Using 12g in SD/HD Models

Byrna sells an optional Boost adapter that allows SD, EP, and HD models (which normally use 8g CO₂) to accept 12g cartridges instead. This increases shot capacity by approximately 50%.

With the Boost adapter installed:

• SD with 8g: 20-22 shots
• SD with 12g (via Boost): ~30 shots

Trade-offs:

• Boost adapter requires installation (not plug-and-play)
• Adds bulk to the launcher frame
• 12g cartridges are slightly larger/heavier

Not compatible with: Byrna CL (no Boost adapter available for CL)

If you want extended shot capacity without buying an LE or TCR, the Boost adapter is a viable option for SD/HD owners. However, for most users, simply carrying a spare 8g cartridge is simpler than installing the adapter.

Questions People Ask About Byrna CO₂

Which CO₂ size does my Byrna use?

Byrna SD and Byrna CL use 8g CO₂. Byrna LE and TCR use 12g CO₂. Byrna Mission 4 uses 88g CO₂ (or 12g depending on configuration). Check your launcher’s manual or product page to confirm which size you need.

How many shots do I get per CO₂ cartridge?

SD (8g): 20-22 shots. CL (8g): ~15 shots. LE (12g): 17-20 shots. TCR (12g): 20-25 shots. Mission 4 (88g): 55-60 shots. Shot counts are at room temperature; cold weather can reduce capacity by up to ~30-40%.

Can I use regular paintball CO₂ in my Byrna?

Byrna recommends using Byrna-brand CO₂ cartridges because they’re tested for proper puncture and performance. Byrna warns that some off-brand cartridges may not puncture correctly, and many users report issues with certain brands. Using non-conforming CO₂ can void your warranty.

How long does CO₂ last after I puncture it?

Once punctured, CO₂ typically begins leaking and may lose most usable pressure within 24-48 hours. If you fire your launcher and store it, the CO₂ will likely be mostly empty within 2 days. For home defense staging, replace punctured CO₂ every 2-3 months or use Byrna‘s pull-pierce system (which keeps CO₂ unpunctured until first trigger pull).

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

The oiler cartridge (included in every 10-pack) lubricates your launcher’s internal seals. Use it every 10 standard CO₂ cartridges to prevent dry seals, velocity drops, and misfires. Skipping it causes long-term performance degradation.

Can I store CO₂ cartridges in my car?

Not recommended for long-term storage. Cars reach extreme temperatures in summer (120°F+) and winter (below freezing). Store unpunctured CO₂ at 50-80°F in a cool, dry location. Carry CO₂ in your vehicle as needed, but don’t leave cartridges in hot/cold cars for weeks.

Why does my Byrna get fewer shots in cold weather?

CO₂ pressure decreases in cold temperatures. Below 40°F, expect up to ~30-40% reduced shot capacity and lower velocity. Keep spare cartridges warm in inside pockets to maintain performance in winter conditions.

Can I use 12g CO₂ in my SD or CL?

Not without modification. SD can use 12g if you install the Byrna Boost adapter. CL cannot use 12g (no adapter available). LE and TCR require 12g and cannot use 8g. Always use the correct size for your launcher.

Final Thoughts: Byrna CO₂ Best Practices

Byrna CO₂ cartridges are simple—use the right size for your launcher, use the oiler cartridge every 10 rounds, and replace punctured cartridges if you’re staging for defense. The most common mistake is leaving punctured CO₂ in a launcher for weeks and expecting it to work when needed. It won’t. CO₂ typically loses usable pressure within 24-48 hours after puncture.

If you’re carrying or staging a Byrna for self-defense, either keep it loaded with an unpunctured CO₂ cartridge (using Byrna‘s pull-pierce system) or replace the CO₂ every 2-3 months. Temperature matters too—cold reduces shot capacity, hot can over-pressurize. Store spare CO₂ at room temperature and carry extras if you’re using your launcher in extreme conditions.

For complete details on which Byrna model to choose and how CO₂ capacity factors into defensive performance, see our Best Byrna Guns guide and individual product reviews.

Ready to stock up? Most pistol owners need Byrna 8g CO₂ cartridges. LE/TCR owners need Byrna 12g CO₂ cartridges. Always use the oiler cartridge every 10 uses.

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Disclaimer: This article is for informational purposes only. Always follow manufacturer instructions for CO₂ installation, storage, and use. Improper handling of compressed gas cartridges can cause injury. Some links may be affiliate links. If you purchase, we may earn a small commission at no additional cost to you. Prices and availability are subject to change—please verify current details before purchasing.