HPA Airsoft UK: The Complete Guide
What is HPA airsoft?
HPA (High Pressure Air) replaces a gearbox or a gas magazine with compressed air, fed from an external tank into an electropneumatic engine in the gun. The engine fires each BB with a precisely metered pulse of air, delivering instant trigger pull, rock-steady FPS from shot to shot, and simple adjustment of power and rate of fire. It’s the system behind most high-end speedsoft and a lot of serious skirmish builds.
What do I need to run HPA?
Four things beyond the gun itself. Think of it as a chain from air source to muzzle:
| Part | What it does | Shop |
|---|---|---|
| HPA tank | Stores the compressed air (48ci and 68ci are the common sizes) | HPA Tanks |
| Regulator | Steps tank pressure down to the ~80–140psi your engine wants | HPA Regulators |
| HPA line | The hose that carries air from the regulator to the gun | HPA Lines |
| Engine / FCU | The electropneumatic unit inside the gun (built in on HPA guns; a conversion kit on AEGs) | HPA Engines |
If you buy a purpose-built HPA rifle like a Wolverine MTW, the engine and FCU are already fitted — you just add a tank, regulator and line. If you’re converting an AEG, you add an engine kit as well.
How do I set it up? (step by step)
- 1. Fit a regulator to your tank (or use an on-tank regulator like the STORM Category 5).
- 2. Set the regulator to your engine’s recommended pressure (commonly 80–140psi — check your gun).
- 3. Connect the line from the regulator to the gun’s air inlet.
- 4. Fit a battery for the FCU if required, load a magazine, and chronograph before you play.
Do I need a line, or can I go lineless?
Two ways to carry the air. A remote line runs from a tank in your rig to the gun — flexible and cheap. A lineless setup puts a small tank in the stock, so there’s no hose at all: the WRAITH X stock does this for the MTW, giving roughly 1,000 shots per 13ci tank with nothing trailing to your rig.
What does an HPA setup cost to get going?
Beyond the gun, budget for a tank, a regulator and a line. There’s a wide range — a budget aluminium tank with an included regulator is the cheapest start, while a carbon-fibre tank plus a premium regulator costs more but is lighter and lasts longer. See the live collections for current pricing; we can build a complete package to any budget.
Is HPA right for me? (pros and cons)
| Pros | Cons |
|---|---|
| Near-instant trigger response | Requires a tank, regulator and line |
| Excellent FPS consistency in all weather | A tether to the tank (unless lineless) |
| Easy to tune power and rate of fire | More upfront kit to buy than a basic AEG |
| Fewer wearing parts than a gearbox | You’ll need to refill tanks (dive shops / sites / compressor) |
Frequently asked questions
Is HPA legal in the UK?
Yes. HPA guns are subject to the same rules as any airsoft gun — site FPS limits and, for RIFs, UKARA or another valid defence at purchase.
What pressure should I run?
Most airsoft HPA engines run around 80–140psi — always use your specific gun’s recommended figure and a secondary regulator.
How many shots per tank?
It varies with tank size and tune, but a lineless 13ci setup gives roughly 1,000 shots, and a 68ci tank is the popular all-day field size.
Can I convert my AEG to HPA?
Often yes — a drop-in engine like a PolarStar or Wolverine kit replaces the gearbox internals. Compatibility depends on your gearbox version.
Where do I refill the tank?
Many airsoft sites, paintball fields and dive shops fill HPA tanks. A home compressor is an option for regular players.
Which HPA rifle should I buy first?
See our best HPA rifles guide and the Wolverine MTW comparison — the MTW is the usual first serious HPA rifle.