PolarStar Jack HPA Engine M249 – Drop-In Conversion

The PolarStar Jack HPA Engine delivers premium air-powered performance without the premium price tag. Engineered for players who want reliability, consistency, and upgrade potential in their M249 platform, the JACK™ replaces your original gearbox cylinder with a sleek, efficient HPA solution.

Key Features

• Drop-in cylinder replacement – minimal modification required
• Universal gearbox compatibility – works with centre-line nozzle systems across multiple versions
• PolarStar filter fitting pre-installed – connect to your air supply immediately
• High-performance HPA conversion – consistent velocity and trigger response
• Affordable entry to air-powered systems – no custom builds needed
• Proven PolarStar engineering – trusted by milsim and competitive players

Real-World Use Cases

The JACK™ suits skirmishers upgrading an existing M249 AEG, milsim players requiring reliable sustained fire, and anyone seeking tunable velocity without full gearbox replacement. Whether you’re running a support role or testing HPA before committing to a full engine conversion, the JACK™ delivers.

Technical Specifications

• HPA system type – drop-in cylinder
• Nozzle compatibility – centre-line configurations
• Filter fitting – PolarStar integrated
• Air source – standard HPA tank and line required (sold separately)

Compatibility & Upgrades

The JACK™ is designed to fit gearboxes with centre-line nozzle geometry. Before purchase, confirm your M249 gearbox version matches this specification. Once installed, you’ll connect to an HPA regulator and tank via the included filter fitting. Upgrade potential is high – many players pair this with aftermarket regulators and air lines for precision tuning.

UK Legal & Site Notes

HPA systems in the UK remain subject to site chronograph testing and local FPS limits (typically 328–350 FPS depending on your venue). Always verify your site’s HPA rules before deployment. The JACK™ itself is unrestricted; velocity is controlled by your air source pressure and regulator.

Order the PolarStar Jack HPA Engine today and experience affordable, high-performance air conversion for your M249.