In short
- GBB means gas blowback. Gas in the magazine fires the BB and cycles the slide or bolt. A GBBR is a gas blowback rifle.
- Magazines are the real cost. A gas magazine holds about 30 BBs, carries its own gas and valves, and you need several.
- Cold takes the pressure away. At 5 °C propane, the base of green gas, holds about a third less pressure than at 20 °C. In a British winter a gas rifle stays at home.
- Start on a common platform. A Hi-Capa or Glock-style pistol, or an M4 gas rifle: magazines, parts and advice are easy to find.
- A used gas gun needs a leak test. Fill every magazine with gas and listen for a hiss as soon as it arrives.
How gas blowback works
In a gas blowback gun the magazine is the engine. It holds the BBs, a reservoir of liquid gas, usually green gas, the standard airsoft gas, and a valve on top. An electric gun (AEG) compresses air with a battery, a motor and a piston. A gas gun has none of those: no motor whine, only a crack and a kick.
That is the whole appeal of gas blowback airsoft, and the source of every drawback further down.
One shot, four moments
-
The valve opens. The hammer strikes the valve on the magazine and a burst of gas escapes.
-
The BB leaves. The first part of that gas pushes the BB down the barrel.
-
The slide flies back. The rest drives the slide, the moving top half of a pistol, or the bolt of a rifle backwards against a spring. That is the kick.
-
The next BB loads. The spring pushes everything forward and feeds the next BB. On most models the slide or bolt stays open when the magazine is empty.
GBB pistols
Most players meet gas through a pistol. A gas airsoft pistol is small, its magazine holds 20 to 30 BBs, and nobody expects a back-up pistol to carry a whole game. Two designs dominate. The Hi-Capa from Tokyo Marui, a wide-bodied relative of the classic 1911 pistol, is the one other makers copy and tuners build on. Glock-style pistols are the plain, dependable alternative.
Pistols in the webshop
Gas, CO2 and spring pistols together; the product page names the system.
In stock, ships right away
GLOCK (Umarex) Airsoft GBB G18C
In stock, ships right away
ELITE FORCE (Umarex) Airsoft CO2 H8R Gen2
In stock, ships right away
GLOCK (Umarex) Airsoft GBB G45
In stock, ships right away
GLOCK (Umarex) Airsoft GBB G17 Gen4GBBR rifles and why people love them
A GBBR does to a rifle what blowback does to a pistol. The bolt slams back and forth, the rifle kicks into your shoulder, and you reload as on the real thing.
That is why people love them, and why they suit milsim, games that imitate military operations: a magazine of about 30 BBs fits rules that limit you to what a real magazine holds.
A gas rifle, honestly
Pros
- Recoil and sound no electric rifle matches
- Handles like the real thing: bolt, reloads, empty magazine
- No battery, no motor, no wiring
- About 30 BBs per magazine makes every shot count
Cons
- Magazines are heavy, dear and hold few BBs
- Weak and unreliable in the cold
- Wants cleaning and oil after every game day
- Energy moves with the temperature
Magazines: the real cost
The gun is the small part of the bill. Every gas magazine is a metal pressure vessel with two valves and a set of seals. It weighs and costs several times what an electric magazine does, and holds a fraction of the BBs. A game day takes five or six for a rifle, two or three for a pistol.
Then there is the gas: a can goes along to every game. No amounts here; the shelves show today's prices.
- Tokyo Marui Hi-Capa 5.1, gas pistol
- 31
- Tokyo Marui M4A1 MWS, gas rifle
- 35
- WE L85, gas rifle
- 30
- Ares L85, electric rifle
- 130
Source: tokyo-marui.co.jp, weairsoft.com and aresairsoft.com, read on 12 November 2026
Gas pistol against gas rifle
- Gas pistol
- Gas rifle
-
Reliable over a full day
- Gas pistol
- 4 out of 5
- Gas rifle
- 3 out of 5
less is asked of a back-up gun
-
Easy on the wallet
- Gas pistol
- 3 out of 5
- Gas rifle
- 1 out of 5
a rifle needs five or six magazines
-
Copes with cold
- Gas pistol
- 3 out of 5
- Gas rifle
- 2 out of 5
a pistol magazine warms in a pocket
-
Easy upkeep
- Gas pistol
- 4 out of 5
- Gas rifle
- 2 out of 5
a rifle has more seals and moving parts
-
What the realism adds
- Gas pistol
- 3 out of 5
- Gas rifle
- 5 out of 5
a kicking rifle changes how you play
Maintenance and leaking seals
Gas guns fail in small ways: a seal dries out, a valve sticks, a magazine hisses. The rubber seals, or O-rings, stay supple with silicone oil, and a magazine stored empty dries out.
After every game day
-
Empty and wipe
Take the BBs out and wipe the dirt off gun and magazines.
-
Oil the moving parts
A drop of silicone oil on the slide rails or the bolt, and on the magazine valves. You find it under maintenance.
-
Store with a little gas
A short burst keeps the seals pressed in place. Keep magazines out of a hot car: Tokyo Marui warns against temperatures above 40 °C.
-
Listen before the next game
Fill each magazine the evening before. A hiss means a seal to replace, at home rather than at the site.
Winter performance in the UK
Gas guns run on the pressure of the gas in the magazine, and that pressure follows temperature. The colder the liquid gas in the magazine, the less push each shot gets. Firing makes it worse: expanding gas cools the magazine, so rapid fire weakens every next shot. Players call that cooldown.
In a British winter that means short range and a sluggish slide. A pistol kept in an inside pocket copes; a rifle asked to carry the game does not. Many owners run an AEG, the standard electric airsoft gun, through the cold months and bring the gas rifle out in spring.
- at 5 °C, a winter morning
- 5.5 bar
- at 20 °C
- 8.4 bar
- at 35 °C, a magazine left in the sun
- 12.2 bar
Source: Vapour pressure of pure propane, calculated by us with the Antoine equation in the NIST Chemistry WebBook (Helgeson and Sage, 1967)
Reader poll
Do you play gas in winter?
- Yes, all year
- Yes, with CO2 or stronger gas
- No, electric in winter
- I do not play gas
Best platforms to start with
Four platforms worth starting on
Hi-Capa and 1911
The tuner's pistol. Tokyo Marui lists its Hi-Capa 5.1 at 31 BBs and 894 g, and other makers sell nearly every part for it. Marui specifies its own gases for it, so ask before you run one on green gas. The slimmer 1911 holds fewer BBs.
Glock-style
Simple, common and easy to find a holster for. Umarex sells the licensed Glock pistols. A good first gas gun if you want a sidearm and not a project.
M4 gas rifle
The safe rifle choice, because the M4 is everywhere. Tokyo Marui lists its M4A1 MWS at 35 BBs per magazine and just under 3 kg. Gas magazines rarely fit across makers, so pick the system first.
AK gas rifle
A heavy bolt and a hard kick. Choose it for the feel, and check that spare magazines for that exact model are in stock before you buy the rifle.
Gas right now: used gas guns against new pistols
Live figures from our marketplace and our webshop.
- listings in GBB on the marketplace
- more than 600
- middle asking price: half ask less, half ask more
- €278
- eight out of ten asking prices fall in this range
- €100 – €800
- products in stock in Pistols in the webshop
- 76
- lowest price of what is in stock in Pistols
- €25
- brands in stock in Pistols
- 4
Airsoft Bazaar data Measured on 13 November 2026
Buying a GBB second-hand
Used gas blowback guns are good value, because sellers often include the magazines that cost so much new. They are also where a tired seal hides. Ask for a video of the gun firing a full magazine, and count the magazines in the photos.
Checks on a used gas gun
0 of 7 ticked
Used gas blowback guns on the marketplace
Pistols and rifles, often with spare magazines.
Frequently asked questions
What does GBBR mean?
Gas blowback rifle. Gas from the magazine fires the BB and drives the bolt back and forth, so the rifle kicks and cycles like the real one. GBB, gas blowback, is the general word and in practice often means a pistol.
How does gas blowback work?
The hammer knocks open a valve on the magazine. Part of the escaping gas pushes the BB out, the rest throws the slide or bolt backwards, and a spring returns it and loads the next BB. Everything that drives the gun sits in the magazine.
Are GBBRs reliable enough for a full game day?
In mild weather, with clean and oiled magazines, yes. Take five or six magazines, a can of gas and spare seals, and expect more upkeep than with an electric rifle. In the cold a GBBR stops being dependable.
Do GBBs work in cold weather?
Poorly. At 5 °C propane, the base of green gas, holds about a third less pressure than at 20 °C, and firing cools the magazine further. A pistol kept warm in a pocket still works for a few shots; a rifle loses range and stops cycling.
How much do magazines and gas cost?
More than the gun suggests. A gas magazine costs several times an electric one and holds about 30 BBs, a rifle needs five or six, and gas is used up at every game. The shelves in this guide show today's prices. Our webshop does not ship gas to the UK.
Which GBBR platform should I start with?
An M4, because magazines, parts and knowledge are easiest to find. Pick the maker's system first, since gas magazines rarely fit across brands. If you are new to gas altogether, a Hi-Capa or Glock-style pistol is the gentler start.
Sources
- Propane, phase change data (Antoine equation parameters) NIST Chemistry WebBook, 12 November 2026
- Winter: the coldest season Met Office, 12 November 2026
- M4A1 MWS, product page Tokyo Marui, 12 November 2026
- Hi-Capa 5.1 Government Model, product page Tokyo Marui, 12 November 2026
- WE L85 GBB; ARES L85 WE Airsoft; ARES Airsoft, 12 November 2026
2 more sources
- Firearms Act 1968, section 57A (airsoft guns) legislation.gov.uk, 12 November 2026
- Violent Crime Reduction Act 2006, section 36 legislation.gov.uk, 12 November 2026
