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PolarStar CO2 Gas Stock CGS CO2 Insert (Type: 33g)

ID: 13520 (ACC-HPA-10000538)
PolarStar CO2 Gas Stock CGS CO2 Insert (Type: 33g)
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CO2 Cartridges not included.
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The manufacturer of this product enforces a strict minimum advertised price (MAP) policy which excludes this product from any additional discount coupon codes. This item, however, may qualify for free shipping.


  • For use with UGS or CGS stocks as well as most common HPA regulators/air rigs which are able to accept 900psi
  • All inserts equipped with expansion chamber, anti-siphon system, 5 micron filter and check valve
  • UGS requires addition of Milspec Rail (sold separately) before inserts can be used
  • Standard ASA threads on all inserts allowing use with standard HPA regulators/air rigs
  • Average shot count using an F2 at 1.5J w/ .28g and 6.05x380mm: 12g = ~180 shots, 33g = ~500 shots
  • 33g models accept threaded CO2 cartridges, while the 12g models use the standard 12g cartridges commonly used for Airsoft and Air Guns
  • Insert cannot be pressurized before installation into stock/regulator
Our CO2 inserts are manufactured for both the UGS and CGS stocks and have models for both the 12g and 33g disposable CO2 cartridges in either variant. However, the inserts have more uses than just being paired with one of these stocks. Since they are equipped with the same standard ASA threads that are on a HPA tank, they can also be threaded into a conventional regulator to make an extremely compact air rig.

The only difference between the UGS and CGS inserts is the diameter of the tube. The CGS inserts are narrower since they are designed to fit inside of a CGS's Milspec buffer tube while the UGS inserts are made to the same diameter as a Milspec buffer tube. This means by changing out the stock's rail you are able to reconfigure your UGS from running the standard 13/3000 HPA tank to a low profile, Milspec buffer tube sized cylinder so you can use Milspec AR buttstocks.

Now, it is commonly known that you should not use CO2 to power an HPA engine since if liquid CO2 gets down-stream of the regulator it can cause a spike in pressure which is unsafe and can damage the sensitive components of the engine. So how is it that we're making something like this? Our CO2 inserts are specifically designed to allow you to safety run your HPA engine off of CO2. These inserts feature an integral expansion chamber, anti-siphon system, 5 micron filter and check valve to prevent liquid CO2 from entering the regulator regardless of the rifle's or air rig's orientation. As an added benefit, the internal check valve also prevents gases from escaping the expansion chamber while switching out cartridges so as to conserve as much CO2 as possible when performing a "combat reload" and allowing several full-power shots even while when the CO2 cartridge has been removed.

The 33g models accept threaded CO2 cartridges that are commonly used for inflating life vests while the 12g models use the standard 12g cartridges commonly used for Airsoft and Air Guns. The 33g cartridges are simply screwed into the receptacle at the bottom of the insert's bore which pierces the seal to release the CO2. The 12g cartridges are pushed down into the pierce pin using a uniquely designed end cap equipped with a multi-start thread. The multi-start thread consists of four intertwined threads running parallel to one another. Intertwining threads allow the lead distance of a thread to be increased (in this case, an increase of 4X) without changing its pitch. In layman's terms this means it has the strength of a slower thread without sacrificing speed. The cap only needs to be turned 270 degrees (3/4 rotation) from first thread engagement to the point that it pierces the cartridge and seals making changing cartridges an extremely fast and reliable process.

So, you are probably wondering how many shots can you get out of these things? Based on an F2 running at 1.5J w/ .28g through a 6.05x380mm barrel, a 12g will average approximately 180 shots while the 33g will average approximately 500 shots. While these may not be the greatest if your playing style embraces the "accuracy through volume" concept, they are ideal for milsim scenarios where shots counts are lower and realism is higher.

Manufacturer: PolarStar


Compatibility: For use with the UGS Universal Gas Stock system from PolarStar.
Material: Aluminum, Brass

About PolarStar

PolarStar Precision Airsoft was formed in January 2009 to fill a need for high quality, precision manufactured airsoft components designed for performance and longevity.The 2011 release of the patented Fusion Engine HPA system marked a change in direction for PolarStar. The focus shifted from developing upgrade components within the constraints of existing systems to developing innovative HPA systems and accessories which replace the aging AEG technology.PolarStar Airsoft 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 began by servicing the automotive racing industry through the design and producing systems and components from art to part. 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. In addition to our own product line, PolarStar also offers engineering and manufacturing services tailored to the airsoft industry.

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