Updated September 2026 · Camstar Sports technical desk
One 12-gram cylinder, 30 to 60 shots, no cocking between them. How the gas system actually works, where it beats a spring pistol, where it does not, and what it costs to run for a year.
See the Star RX Gen 3 →Written by the Camstar Sports technical desk, Lucknow · Reviewed September 2026
A CO₂ air pistol uses a small cylinder of liquefied carbon dioxide — almost always 12 grams — as its power source. Piercing the cylinder releases gas at a steady pressure, and each trigger pull meters a measured dose behind the pellet. Because the gas does the work instead of a spring you compress by hand, the pistol can be semi-automatic: no cocking stroke between shots.
That single design choice is the whole argument for and against the system. It buys you speed and near-zero recoil. It costs you a consumable, and it makes the gun sensitive to temperature in a way spring and PCP pistols are not.
Inside a sealed 12 g cartridge, CO₂ sits mostly as liquid with gas above it. When you screw the cartridge into the grip, a pin pierces the foil cap and the gas fills a small valve chamber. Pull the trigger and a hammer strikes the valve, opening it for a few milliseconds — long enough for a measured volume of gas to expand behind the pellet and push it down the rifled barrel.
The important part is what happens next: as gas leaves the cartridge, some of the remaining liquid boils to replace it, and the pressure returns almost to where it started. That self-regulating behaviour is why shot-to-shot consistency on a CO₂ pistol is good right up until the liquid runs out — and why the last few shots of a cartridge drop off a cliff rather than fading gradually.
Boiling liquid absorbs heat, and it takes that heat from the cartridge and the metal around it. Shoot a full magazine quickly and you will feel the grip chill; you may see frost on the cartridge housing. Colder liquid means lower pressure, which means a slower pellet. Wait fifteen seconds between shots and the cylinder rewarms from the surrounding air, which is the simplest way to keep velocity consistent across a session.
| CO₂ | Spring-piston | PCP | |
|---|---|---|---|
| Shots per charge | 30–60 per 12 g | Unlimited | ~90 per fill |
| Cocking | None — semi-auto | Every shot | Bolt only |
| Recoil | Negligible | Forward lurch | Near zero |
| Cold weather | Loses velocity | Unaffected | Unaffected |
| Running cost | Pellets + gas | Pellets only | Pellets + pump |
| Extra kit | None | None | Pump or tank |
Short version. Buy spring to learn, CO₂ for speed, PCP for group size. If you can only own one and you are new to the sport, a spring pistol at ₹8,400 teaches you more per rupee than anything else on this page.
Take a shooter who fires 100 pellets a week — a realistic figure for someone practising twice a week at home. That is 5,200 pellets a year, or about 17 tins of 300 at ₹450 each, so roughly ₹7,800 in pellets.
On CO₂, at a conservative 40 shots per cartridge, 5,200 shots needs 130 cartridges. At ₹550 per five-pack that is about ₹14,300 in gas, bringing the year to roughly ₹22,100. The same shooting on a spring pistol costs the ₹7,800 in pellets and nothing else.
Worth knowing before you buy. Over three years of steady practice the gas can cost more than the pistol did. That is not an argument against CO₂ — it is an argument for being honest about why you want it. If the answer is “semi-automatic practice I cannot get any other way”, it is money well spent. If the answer is “it looked good in the video”, buy the spring pistol.
The Star RX Gen 3 at ₹25,500 is India's first semi-automatic CO₂ air pistol: 32 rounds across four rotary magazines, a single 12 g cartridge in the grip, roughly 5.5 joules of muzzle energy, and a full metal body. It is built in Lucknow, carries a 12-month manufacturing warranty, and its seals, sights and small parts are stocked individually as spares rather than only as a whole-gun replacement.
At 5.5 joules it sits at about a quarter of the 20-joule legal threshold, so it needs no licence anywhere the central rule applies. Full specifications and the current colour options are on the product page, and it is compared against the imported alternative in Star RX Gen 3 vs Umarex XBG.
What is a CO₂ air pistol?
A CO₂ air pistol is an air pistol powered by a small disposable cylinder of liquefied carbon dioxide, usually 12 grams. Piercing the cylinder releases gas at a steady pressure, and each trigger pull meters a measured dose behind the pellet. Because the gas does the work, there is no spring to cock between shots — which is what allows a CO₂ pistol to be semi-automatic. In India these are legal without a licence provided muzzle energy stays under 20 joules under the Arms Rules 2016.
How many shots does one 12 g CO₂ cartridge give?
Roughly 30 to 60 shots from a 12 gram cartridge, depending on temperature and how fast you shoot. At 30°C you will be near the top of that range; at 10°C on a winter morning in north India, closer to the bottom. Shooting quickly also drops the count, because the rapid gas expansion chills the cylinder and lowers pressure — pause 10 to 15 seconds between shots and you will get noticeably more from the same cartridge. A five-pack of 12 g cylinders costs ₹550, so the gas works out to roughly ₹2 to ₹4 per shot.
Is a CO₂ pistol better than a spring pistol?
Neither is better; they train different things. A CO₂ pistol has almost no recoil and fires as fast as you can aim, which suits trigger-reset drills, rapid re-acquisition and sustained practice sessions. A spring pistol recoils forward as the piston slams home, needs cocking between every shot, and forces a slower deliberate routine — which is the better teacher for a first-time shooter and costs nothing to run beyond pellets. Most people should learn on spring and add CO₂ when they specifically want speed.
Do CO₂ pistols lose power in cold weather?
Yes, and it is the single real drawback of the system. CO₂ pressure inside the cylinder is a function of temperature, so as the ambient temperature falls the gas delivers less energy per shot and the pellet flies slower. The effect is mild in most of India for most of the year, but it is noticeable on a cold Delhi or Lucknow winter morning, and it compounds if you shoot fast enough to chill the cylinder. Spring and PCP pistols are unaffected.
Do I need a licence for a CO₂ air pistol in India?
No, provided the pistol produces under 20 joules of muzzle energy. The Arms Rules 2016 keep low-energy air weapons outside the licensing regime of the Arms Act 1959, so there is no arms licence, no police verification and no district-magistrate application. The buyer must be 18 or older. A small number of states have issued notifications asking owners to intimate their local police station, so confirm your own state. The Star RX Gen 3 produces roughly 5.5 joules, about a quarter of the legal threshold.
How do you store a CO₂ pistol between sessions?
Unscrew and discard the cartridge once you have finished shooting, then dry-fire once to release any residual gas. Leaving a pierced cartridge in place holds the face seal under constant pressure, and over weeks that is what flattens the seal and causes the slow leaks people mistake for a faulty gun. Store the pistol unloaded, in a dry place, away from children, with a light film of oil on external metal during monsoon.