PolarStar JACK HPA Conversion Kit — 9 Platforms
PolarStar JACK HPA Conversion Kit — 9 Platforms
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DETAILS
DETAILS
- description
An AEG wears out from the inside. Gears shim themselves out of true, the piston sheds teeth, the spring settles and the motor slows as the battery drains. An HPA engine removes every one of those parts, and the JACK is the version that does it without asking you to learn a new hobby first.
It uses a single-solenoid open bolt system, which is simpler to set up than a dual-solenoid engine while still giving excellent air efficiency and consistent velocity. Fewer things to configure, fewer things to get wrong, and a reputation for reliability that has kept it in the range for years.
Tuning covers what actually matters: dwell and rate of fire are both adjustable, so you can set the gun for your site limit and your preferred trigger response without a laptop full of settings.
The nine variants are the point of this listing. Alongside the standard V2 M4/M16 and V3 AK, PolarStar make platform-specific versions for the M249, M60, KAC LMG, VFC HK417, S&T TAR-21, Ares M4 and Ares Amoeba EFCS / APS ESE. Support gunners in particular are badly served elsewhere, and this is one of the few genuine routes to putting an LMG on air.
Which PolarStar engine?
| JACK | F2 | Kythera | |
|---|---|---|---|
| Type | Single solenoid, open bolt | Dual solenoid | Mechanical, closed bolt |
| Battery / FCU | Required | Required | None |
| Tuning | Dwell and ROF | Independent nozzle and poppet control | Mechanical only |
| Rate of fire | High | Very high | Semi-focused |
| Best for | Affordable, dependable HPA | Competitive builds | DMR and battery-free builds |
Specifications
| Specification | Detail |
|---|---|
| Type | Single-solenoid open bolt HPA engine |
| Power | HPA — external tank and regulator required |
| Electronics | FCU and battery required |
| Tuning | Dwell and rate of fire |
| Platforms | V2 M4/M16, V3 AK, M249, M60, KAC LMG, VFC HK417, S&T TAR-21, Ares M4, Ares Amoeba EFCS / APS ESE |
| Included | JACK engine, wiring harness, installation components (variant dependent) |
| Brand | PolarStar |
Good to know before you buy
Select the correct platform variant before ordering — these are not interchangeable, and the M4/M16 and AK versions are priced differently from the specialist ones.
You will also need a tank, regulator, line, a battery and an FCU. And you will need the correct nozzle for your gearbox — that is not optional, and getting it wrong causes feeding problems that look like engine faults.
Frequently asked questions
Which variant do I need?
Match it to your gearbox and rifle. V2 M4/M16 and V3 AK cover most builds; the rest are platform-specific. Send us your make and model and we will confirm before you order.
JACK, F2 or Kythera?
JACK for a dependable, affordable conversion. F2 for maximum tuning control on a competitive build. Kythera if you want no battery and a mechanical trigger. The table above sets out the differences.
Do I need a nozzle as well?
Almost certainly. PolarStar use a numbered nozzle system matched to your gearbox dimensions, and the correct one is essential for feeding and air seal. Ask us and we will identify yours.
What else do I need to run it?
A tank, a regulator, a line, a small battery and an FCU. None are included.
Can you fit it?
Yes. Converting to HPA means stripping the gearbox and rewiring the trigger. We fit, tune and chronograph in the workshop.