Airsoft players have never had this good: more models, more gear, more companies, and more players. What is also important is that the competing airsoft technologies: Gas Blowbacks, AEGs, and HPAs are even getting more improvements in terms of performance and reliability that airsoft players can have a good selection of airsoft models depending on the requirements of the airsoft game they are going to. While Gas Blowbacks are finding their way into more gun models, and the AEG technology is improving in recoil and blowback functions, the HPA also gets an update from PolarStar, whose drop-in HPA-powered gearbox technology is getting raves from airsoft players who are using it.

HPA powered the first big growth of airsoft, where most of the pioneers of airsoft, the Japanese, made their fortunes. The second big growth was ushered by AEGs which cut the umbilical cord of the gas/air tank and allowed easier carry of airsoft guns. But I think airsoft is now on its golden age as the three main airsoft technologies are being continually improved.

HPA-powered airsoft guns lost their luster due to issues of having that snaking hose from the HPA tank to the airsoft gun, which can also be a problem for airsoft players having to worry about the hose snaking around their bodies and getting entangled in obstacles and bushes. Plus, the HPA tank itself is an added weight to the loadout of a player, whereas that space and weight that the tank occupies can be devoted to other needed stuff: hydration and ammo. Gas blowbacks and AEGs are actually technology improvements that were intended to fully replace the HPA-powered airsoft guns. Thus, these two are right now dominating the airsoft market, but they have failed to eradicate the HPA.

One group of airsoft players have kept the HPA alive: the classic airsoft group who have been trading the classic airsoft guns. But since classic airsoft guns are just that, being classics, are already hard to find items. One supplier does HPA powered kits which is Daytona Gas Blowbacks which  is based in Hong Kong, but due to business issues and long waiting times to get their kits, it remains to be such a very niche market in airsoft.

PolarStar Airsoft made a name for itself supplying high quality upgrade parts in the U.S.A. and with their patent-pending HPA "Fusion Engine" technology getting good reviews, it’s something that the airsoft community in the U.S. can be proud of, a U.S. airsoft company that can go head to head against the best airsoft manufacturers in the Far East in terms of innovative airsoft technologies. Whilst the gearbox can be dropped-in to existing AEG AR receivers, PolarStar partnered with VFC to release their PR-15 EPAR (Electro-Pneumatic Airsoft Rifle) Series to provide a complete HPA Fusion Engine equipped airsoft gun. With this partnership, PolarStar can concentrate on improving on their HPA gearbox, since this is what separates the company from the rest.

The question from those who haven't laid their hands on PolarStar's HPA Fusion Engine is "What makes it special apart from the existing HPA-powered airsoft guns?" The answer is their innovative technology that corrects how HPA airsoft guns should work. The problem with the old HPA technology is that you cannot adjust muzzle velocity and cyclic rate separately. Thus, airsoft skirmish sites which have strict regulations on FPS limits may not allow HPA-powered airsoft guns. In AEGs, you can manage this by using MOSFET units, spring changes or changes in gears. Gas Blowbacks are another thing, and you increasing ROF depends on the bolt and gas pressure. With PolarStar, you can make adjustments to both muzzle velocity and cyclic rate separately. PolarStar's HPA Fusion Engine has a Fire Control Unit (FCU) which controls two solenoids that operate separate functions. The FCU is like a MOSFET, that you can adjust the firing rate and adjust the volume of air needed to get the maximum performance given the requirements of the airsoft game you're going to.

Another roadblock is what makes HPA-powered airsoft guns unattractive to airsoft players: the tank system. This is an extra weight as mentioned, and together with the hose, might inconvenience players. However, this can be minimized as HPA tanks nowadays are more efficient and smaller, and MOLLE systems allow for the hose to be strapped to a vest as you can snake it through the MOLLE loops, making them stay there rather than protrude outside the body and issues of entanglement are thus solved.

What users of PolarStar HPA Fusion Gearbox or the EPAR-15 Series like is the performance they can derive from the system. Setting aside the HPA tank system issue, they are happy on how they can configure the system and less worries of maintenance given that there are fewer maintenance issues and power issues as compared to AEGs and Gas Blowbacks. As they can adjust their ROF from 8bps to 30bps, they can also adjust the power from 330fps to 475fps and they have nozzles if you want to restrict the muzzle velocity such as the "1 Joule" nozzle that is more appropriate for CQB games. These nozzles prevent an increase in muzzle velocity even if you apply even more air pressure. Since these nozzles are color-coded, concerns about unregulated HPA-powered airsoft guns can be put to rest as a quick check of the nozzles can show the muzzle velocity limits a PolarStar airsoft gun can have at a given airsoft game.

With their gearbox being able to fit perfectly with existing AEG barrels, airsoft guns powered by PolarStar can expect an even better accuracy as it operates on a principle of less barrel movement results in more accurate results. Since PolarStar HPA Gearbox was designed with the intention to replace AEG gearboxes as drop-in kits for AEG receivers, they can readily use existing (READ: TM-Compatible) M4 AEG magazines --- no more need for special magazines to operate the gun properly.

The PolarStar EPAR-15 series and gearbox are mainly available in the US and are commanding premium prices, but not as expensive as the PTW types. A growing number of airsoft players are acquiring PolarStar units as they are dependable and their cost of ownership is actually less in the long run.

With blowbacks and recoil now getting to be mainstream features in AEGs that PolarStar intends to replace, these will be the main obstacles that the company will have to face as it makes its proposition in the airsoft market. Will they be able to do such given the Daytona HPA Gas Blowbacks are able to deliver those features? We cannot say if the PolarStar engineers are already working on those features. But what is more important is to put the gearboxes and EPAR-15 series on a greater number of hands just to find out how these will fare in a market with more competitors coming in. Since the gearbox are designed for AR platforms, AK players and non-AR fans are left out to enjoy this technology.

Perhaps one thing to increase the spread of the PolarStar technology, once patent application gets approved, is to have the technology licensed to other manufacturers. This approach will open up a larger customer base for the company and revenues can be devoted to further research such as adding more features and diversifying on the type of gearboxes it can be used on.

The big contract that PolarStar got is an order from the Mongolian Army for training purposes, which should add a good chunk of money for them (Grrrr!!! Thumpy's fault, hehe!). But since the airsoft market is their main market, milsim enthusiasts are getting to be more keen on having it. Still, while it's slowly but steadily getting acceptance among airsoft players, PolarStar has to work harder still to dispel doubts by having their technology available in more types of airsoft guns.

For a better understanding of the PolarStar HPA Fusion Engine, you can read Shorty USA's review which is the most exhaustive review of the technology. We highly recommend the review as it's well written and very comprehensive.