Polarstar Jack A&K SR25

The JACK™ system was designed to answer the demand for an affordable, high performance HPA (High Pressure Air) conversion for AEG`s. The system is a drop-in cylinder replacement that is universally compatible with a wide range of gearbox versions that have center-line nozzles.

Similar to its sister product, the F1, it replaces the original gearbox components with a programmable pneumatic system allowing for higher performance and greater reliability over a gear driven system. Although economically priced, JACK™ still retains the same performance and quality you have come to expect from PolarStar products.

JACK™ has only 1 moving part, the nozzle, which acts as its own poppet valve which is piloted by the solenoid. With the exception of the poppet being integral to the nozzle, the valve is similar to the poppet valve used in the previously released Fusion Engine™ and is what gives JACK™ its signature muzzle report. The system itself only has 6 parts and can be completely disassembled by hand in a matter of seconds so the system is very reliable and easy to maintain. 

Just like all other PolarStar HPA conversions, JACK™ also allows for easy velocity adjustment. Using a standard M4 as an example, velocity can be adjusted from below 280fps and up to approximately 500fps with a .20g BB. This can be done simply by adjusting input pressure and poppet dwell to fine tune your rifles velocity in increments of just a few FPS at a time. Maximum velocity potential of the system will vary depending upon the barrels length and tightness of the bore. Longer and tighter barrels will yield a higher velocity while shorter or wider barrels will be yield a lower velocity.

As with all of PolarStar`s electro-pneumatic conversion kits, you can quickly change and adjust key functions of JACK™ via the on-board FCU (Fire Control Unit) which is no bigger than an AEG`s MOSFET and can easily fit inside of a rifles battery compartment along with a small Li-po battery. Using the FCU`s five position joystick and LCD display you will be able to easily and precisely adjust such functions as the systems cyclic rate, fire modes and poppet dwell on the fly.

Although efficiency was not a critical requirement during development, JACK™ does boast some highly respectable figures in this category. This is made possible by its compact and intelligently laid out design which minimizes dead volume resulting in better air flow, faster response and less air used per shot. As a result JACK™ is considerably more air efficient than a bone stock Fusion Engine™ when operating in the same velocity range.


Key Features

• Designed, manufactured and built in the U.S.A..
• Assembled from CNC machined aluminum components with high performance delrin nozzle.
• Universal cylinder design is compatible with numerous gearbox versions.*
• Optimized flow profile, firing point and flow path promotes superior shot consistency and accuracy.
• Capable of functioning in damp and sub-freezing climates without affecting performance or reliability.
• User selectable Semi/Full Auto, Semi Auto Only and Variable Burst modes.
• Independently adjustable velocity and cyclic rate.
• Auto Switch mode allows for proper selector configuration for specific models.
• Easy to use Fire Control Unit (FCU) with LCD display and five position joystick.
• Instantaneous trigger response. Faster than an AEG with a Li-po!

Required for operation: Complete TM Spec AEG rifle with gearbox, Regulated Air Rig, HPA Tank, Battery.

Model suitable for A&K SR25

Package include :

• Polarstar JACK A&K SR25
  
• Trigger board V2
  
• FCU REV3

Please note that instaling a HPA drop in system is recommanded for skilled gunsmith only. The product comes as a spare part and does not come with installation manual. By purchasing an HPA system you take entire responsability of the assembly and upcoming results. For products delivered with a trigger board, contactors / switch are not guaranted by the manufacturer in case of break. We advice to take extreme care when installing the selector plate in order to not break the button. Regarding the trigger switch, it is recommended to block mecanicaly the trigger once the the trigger switch is activated to avoid excessive pressure on it.