How Many Shots From a 12g CO₂ Cartridge?

Quick Answer

One 12g CO₂ cartridge gives about 30 to 60 shots in a typical air pistol. Expect the top of that range in warm weather with slow, spaced shots, and the bottom in cold weather or rapid semi-auto fire. Blowback-slide pistols use extra gas, so they get fewer. In the Star RX Gen 3 (8-shot magazines) that is roughly 4 to 7 full magazines per cartridge.

1. Temperature dictates pressure

While there is liquid left, the pressure inside the cartridge is set by temperature: about 72 bar at 30°C, 57 bar at 20°C and 45 bar at 10°C (standard CO₂ pressure–temperature data). The pistol’s valve needs a minimum pressure to send the pellet out at usable velocity. A warm cartridge stays above that point for more shots; a cold one reaches it sooner. Never heat a cartridge or leave it in a hot car or direct sun: pressure keeps rising with heat.

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.

• Shoot in warmer conditions. A shaded veranda is warmer than an air-conditioned room. Aim for above 25°C, without putting the pistol or cartridges in direct sun.
• 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.

• 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

How many shots does one 12g CO₂ cartridge give?

A single 12g CO₂ cartridge gives roughly 30 to 60 shots in a typical air pistol. The exact number depends mostly on temperature (more shots when it is warm), shooting pace (fewer when you fire rapidly) and whether the pistol has a blowback slide (blowback uses extra gas every shot).

How many magazines does one cartridge give in the Star RX Gen 3?

The Star RX Gen 3 uses one 12g cartridge and 8-shot rotary magazines, four of which come in the box (32 shots). At 30–60 shots per cartridge that works out to about 4 to 7 full magazines, so one cartridge usually covers all four magazines once, and in warm weather often a second partial round. The pistol ships with 2 cartridges.

How many shots does a CO₂ BB gun get per cartridge?

The same physics applies to BB pistols that run on a 12g cartridge: the gas, not the projectile, sets the limit, so expect a similar 30–60 range, with fewer shots on blowback models and in cold weather. Check the maker’s figure for your specific gun.

Why does my CO₂ pistol get fewer shots in winter?

CO₂ pressure falls with temperature: about 72 bar at 30°C, 57 bar at 20°C and 45 bar at 10°C. In the cold the cartridge drops below the pressure the valve needs sooner, so you get fewer full-power shots. This is physics, not a defect. Keep the cartridge at room temperature before loading to offset some of 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 ₹550 for a pack of 5 (₹110 each). At 40 shots per cartridge that is about ₹2.75 of CO₂ per shot. Add ₹1.50 for a Star Match Diabolo pellet (₹450 for 300) and the all-in cost is about ₹4.25 a shot.

Buy genuine Camstar 12g CO₂ cartridges — ₹550 for 5, delivers pan-India within 7–9 days*.