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PolarStar Airsoft Jack V2 Electro-Pneumatic Gearbox Conversion Kit for G&G SR25

[65850 / PS-SJV2-SR25GG]
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PolarStar Precision Airsoft Components (PPAC) was formed in January 2009 to fill the need for precision engineered airsoft upgrade parts. PPAC is a division of PolarStar Engineering & Machine (PSE&M), a unique blend of tenured American toolmakers and a full service CAE/CAD/CAM (Computer Aided Engineering, Design, and Manufacturing), special crafts machine shop keeping alive our proud manufacturing heritage of "Made in the USA".

Founded in 1997, PSE&M specializes in servicing the automotive racing industry by designing and engineering systems and components from "art to part." Whether a unique one off prototype up to and including manufacturing large quantities of finished and tested parts and assemblies. Operating under the auspices of the Delaware Association of Professional Engineers, we retain a Professional Engineer (P.E.) on staff to ensure and certify all design and engineering standards are met.

The JACK System ( codename Simple Jack ) was conceived during the project which the F1 came from ( codename Karl ). The JACK will be the ideal system for the person looking for a basic HPA system that still delivers high performance and reliability while at the same time being economically priced. JACK uses a smaller solenoid as a pilot valve to open a larger poppet valve (similar to the Fusion Engine poppet but integrated as one piece with the nozzle) through which the firing air travels through from the air input line. Since JACK can use a smaller solenoid this helps keep the cost down but by design the system will be slightly less air efficient. It will be considerably more efficient than a stock Fusion Engine. The JACK is an open bolt system and will offer similar performance as far as how the BB goes downrange. This system utilizes a tool-less dis-assembly ( after removing it from the rifles gearbox ) allowing maintenance to be very simple. In fact, this system can be broken down for maintenance in a matter of 15 seconds or less. In regards to the nozzle placement on the JACK, while there is enough room to accommodate offset nozzles, the JACK will remain with a center line configuration. The FCU ( Fire Control Unit ) is similar to the Fusion Engine but with a different firmware since it is only driving one solenoid instead of two. Fusion Engine nozzles will not be compatible with the JACK. Extra nozzles will not be available for the JACK since the system alone can achieve up to 500 FPS to sub 280 FPS by the adjustment of input pressure and dwell. The JACK system nozzle is constructed from delrin, which is known to have good mechanical properties for this specific application. It is strong, lightweight, impact resistant, and temperature stable. The JACK will be compatible with most gearboxes as long as the rifle has a gearbox with a center line nozzle. In most cases, a different nozzle or different internal switchboard will be the only thing required for the JACK to function with different rifle models and gearbox versions.

Manufacturer: PolarStar Airsoft
Model: JACK
Muzzle Velocity: 280 - 500 FPS, Adjustable
Rate of Fire: 1 - 30+ RPS, Adjustable
Fire Modes: Semi, 2-9rd Burst / Semi, Full Auto / Semi Only
PSI Operating Range: 40 - 130 PSI
FCU Voltage Range: 7-10 VDC
Package Includes: JACK, Internal Switch Board, FCU


  • Made in the U.S.A.
  • Adjustable Velocity
  • Adjustable Rate of Fire
  • Center Line Nozzle Design
  • Smaller Solenoid
  • Cost Efficiency

Manufacturer: PolarStar
see 1 reviews | Write a Review
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J. CLARKSON | 2021-09-15
Product Information:
Wonderful conversion kit. Made my busted up SR25 come back to life.



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