Guide · Camstar Sports

How Long Does a 12g CO₂ Cartridge Last?

Real per-cartridge shot counts for airgun pistols — with the physics behind why the number varies so much between winter and summer, or between rapid fire and slow fire.

~5 min read · Updated July 2026

Quick Answer

One 12g CO₂ cartridge lasts 30 to 60 shots in a typical air pistol. Expect closer to 50–60 in hot weather with slow deliberate shooting; closer to 30–35 in cold weather or rapid semi-auto fire. Blowback-slide pistols use more gas than fixed-slide designs, so they get fewer shots per cartridge.

The Real Answer, By Condition

The “30–60 shots” range on the cartridge label is honest but too wide to plan around. Here is what to actually expect in Indian conditions, based on our range testing of the Star RX Gen 3:

Condition	Shots / cartridge
Hot summer (32°C+), slow deliberate shooting, 5s+ between shots	55–65
Warm (25–30°C), normal pace	45–55
Cool (18–24°C), normal pace	35–45
Cold (below 18°C), any pace	25–35
Any temperature, rapid semi-auto fire (1 shot/sec)	25–35
Blowback-slide pistol (Umarex Glock etc.)	20–30

Why the Shot Count Varies So Much

A CO₂ cartridge holds 12 grams of liquid CO₂ under about 60 bar of pressure at room temperature. Each time you fire, the valve releases a small burst of gas — but two things determine how many bursts you actually get:

1. Temperature dictates pressure

CO₂ pressure inside the cartridge is temperature-dependent. At 30°C it’s roughly 65 bar; at 10°C it’s closer to 40 bar. The pistol’s valve needs a minimum pressure to fire the pellet at usable velocity — call it 30 bar. In summer, the cartridge stays above 30 bar for far more shots than in winter, when it hits that threshold much sooner.

2. Firing cools the cartridge

When gas expands (which happens every shot), it absorbs heat from its surroundings — this is adiabatic cooling. The cartridge itself gets noticeably cold during rapid firing. That temperature drop pushes internal pressure down, which pushes usable shot count down. If you fire 30 shots in 30 seconds, the last 10 will be markedly weaker than the first 10. Space shots 3–5 seconds apart and the cartridge stays warmer, giving more total shots.

How to Get More Shots Per Cartridge

Shoot in warmer conditions. Even a covered veranda in the sun is warmer than an air-conditioned room. Aim for above 25°C.
Slow your pace. 5+ seconds between shots gives the cartridge time to warm back up from ambient heat.
Warm the cartridge before loading. A cold cartridge from a cold shelf will underperform. Let it sit at room temperature for 15 minutes first.
Use fresh cartridges. Cartridges stored 3+ years may have slowly leaked and hold less pressure than a fresh one — buy in reasonable quantities you’ll finish in 6–12 months.
Don’t chase max velocity. If your pistol has adjustable velocity, running it at 80% of max uses noticeably less gas per shot.

What This Costs You Per Shot

At Camstar’s pricing (₹110 per 12g cartridge, ₹500 per 300-pellet tin of match-grade Diabolo), the all-in cost of one shot from a Star RX Gen 3 is:

CO₂ cost (assuming 40 shots per cartridge)₹2.75 / shotPellet cost (match-grade Diabolo)₹1.65 / shotAll-in cost per shot~₹4.40 / shot

A 60-shot practice session costs about ₹265. Cheaper than a coffee, and every rupee goes into real trigger time. Bulk pellet tins and 5-cartridge packs bring the per-shot cost down further.

When to Swap the Cartridge

Don’t wait until the pistol clicks empty — by then you’ll have already fired 5–10 weak shots that missed the group. Watch for these signals:

Point of impact drops 2 cm or more below your normal 10m zero
Semi-auto slide fails to fully cycle (in blowback pistols)
Trigger pull produces a soft hiss instead of a normal crack
Pellet visibly loses velocity — appears slower toward the target

Frequently Asked Questions

How many shots does one 12g CO₂ cartridge give?

A single 12g CO₂ cartridge gives approximately 30 to 60 shots in a typical airgun pistol. The exact number depends primarily on ambient temperature (more shots in hot weather), shooting pace (fewer shots when firing rapidly), and whether the pistol is a fixed-slide or blowback-slide design (blowback uses more gas per shot).

Why does my CO₂ pistol get fewer shots in winter?

CO₂ gas pressure drops sharply as temperature falls. At 30°C a fresh cartridge holds enough pressure for 50–60 usable shots; at 15°C the same cartridge may only give 25–35 shots before pressure drops below what the valve needs to cycle. This is physics, not a defect. Warm the cartridge in your pocket for a few minutes before shooting to partially offset the effect.

Does firing quickly waste CO₂?

Yes. Rapid semi-automatic firing cools the cartridge through adiabatic expansion — the gas loses energy as it expands into the barrel. A cold cartridge gives lower per-shot pressure, so shots per cartridge drops when you fire fast. Spacing shots 3–5 seconds apart in warm weather maximises total shots per cartridge.

How can I tell when my CO₂ cartridge is empty?

You will notice muzzle velocity drop — pellets will visibly slow, and often will not fully cycle a semi-automatic slide. Some pistols emit a soft hiss when you pull the trigger on a spent cartridge instead of the normal crack. Change the cartridge when point of impact drops more than 2 cm below your normal 10m zero.

Can I leave a CO₂ cartridge in the pistol between sessions?

For a day or two, yes — it will slowly leak but the pistol is still ready to shoot. For weeks or months, no — the constant pressure will damage the pistol's seals over time and the cartridge may leak fully. Remove the cartridge if you will not shoot for more than 5–7 days.

How much does one shot cost with a 12g CO₂ pistol?

Camstar 12g cartridges are ₹110 each (₹550 for a pack of 5). At 40 shots per cartridge, that's about ₹2.75 in CO₂ per shot. Add roughly ₹1.50 for a match-grade pellet and the all-in cost per shot is under ₹5. Cheaper than any other trigger-time you can buy in India.