High-pressure air (HPA) airsoft guns are actually nothing new. During the early years of what we now call "airsoft", our airsoft guns were powered similarly to the HPA guns we see today. Though today these guns can be somewhat of a controversial product among the airsoft community, these relatively uncommon airsoft guns can provide a number of key advantages and unique drawbacks as well. To help you understand why airsoft players are so divided about HPA guns, we'll address the question of what is HPA airsoft and take a look at the various pros and cons associated with HPA airsoft guns. 

What is an HPA Airsoft Gun?

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Unlike most gas-powered guns that feature internal gas cartridges or canisters, HPA airsoft guns are powered by an external canister of pressurized air much like most paintball guns. As we previously mentioned, in the past before the advent of the AEG, this was also how many airsoft guns were powered - using external tanks. These large, external canisters provide HPA guns quite a bit more oomph than traditional gas-powered guns, allowing for faster rates of fire and higher FPS. While this may seem to make HPA guns the clear choice for anyone who wants to be as competitive as possible on the airsoft field, there are a number of drawbacks to HPA guns that we will get to later. For now, just understand that an HPA airsoft gun is a gun that is traditionally powered by an external canister of pressurized air as opposed to an internal canister of C02 or green gas, though, there are many brands pioneering technologies that can allow for HPA systems to be used in conjunction with Co2 cartridges or a tank that attaches directly onto your airsoft gun.  

HPA vs AEG Guns: What's the Difference?

Automatic electric guns (AEGs) and HPA guns both work by using pressurized air to accelerate BBs out of the gun. In an AEG, though, this pressurized air is created within the gun before each shot via a mechanical system that is powered by batteries. Check out our blog on the topic of AEGs as we go more in-depth on the topic. In an HPA gun, pressurized air is stored in an external canister and delivered to the gun with each pull of the trigger rather than relying on a mechanical process to create pressurized air within the gun itself. However, there are examples of pneumatic systems that are fully mechanical, made for players that want a more realistic trigger and firing feel but this still relies upon an external source for air pressure.

Pros and Cons of HPA Guns

Now that we've addressed the question of what is HPA airsoft, let's take a look at the various advantages and drawbacks that these unique airsoft guns provide. HPA guns are controversial largely due to the fact that the pros and cons of these guns are both so pronounced. The benefits of HPA guns make them an alluring option for many airsoft players, but the drawbacks of these guns can be considerable as well. 

Advantages of HPA Guns

  • High FPS - The adjustability of HPA airsoft guns can make them the most powerful of all airsoft gun types, meaning that they can deliver the highest possible FPS in the easiest way. This is done by controlling the air pressure's PSI. The higher the PSI (air pressure) the higher the FPS can be. High FPS means that your shots will be more accurate at longer ranges as each BB will be able to fly through the air with more energy behind them.
  • FPS Consistency - HPA airsoft guns also offer more consistent FPS between shots. This is achieved using either an electronic circuit board that actuates a valve, or in the case of the pneumatic systems, a pressurized valve that can be manually opened and close with the pull of a trigger (as seen in fully mechanical HPA guns). This high degree consistency comes from the gun only allowing the same volume of air into an expansion chamber that then pushes out the BB. The parts that open and close these valves are operated extremely precisely to achieve this type of performance with only a +/- 1 or 2 FPS. With other types of airsoft guns, FPS can sometimes vary more dramatically between shots, leading to more inconsistent BB travel as they exit the barrel which ultimately leads to missed shots downrange. 
  • Faster Rate of Fire - In addition to offering higher FPS, the increased power that HPA guns provide also means that they are able to offer faster rates of full-auto fire. This can also be adjusted using electroics as well as some brands facilitate this kind of rate of fire adjustment without having to increase the overall power of your gun. However, these systems are usually slightly more pricey.
  • Adjustable FPS - If you've ever wondered how to lower FPS, just know that an HPA gun makes this process relatively straightforward and simple. As previoulsy stated, HPA guns offer adjustable FPS and while it may seem like being able to lower the FPS of your gun wouldn't be much of a benefit compared to increasing it, some airsoft fields have FPS limits in place and will require you to lower the FPS of your HPA gun before they allow you to use it. With many AEGs or even gas guns, the process necessary to achive this usually requires you to do some disassembly. With HPA guns, you usually just need to simply lower the PSI coming out of your air tank, and you are done. No disassembly required.
  • Simpler Internal Design - Compared to AEGs, HPA airsoft guns don't have nearly as many moving parts. This makes HPA guns a little more reliable and less likely to malfunction. HPA guns revolve around their engines and as long as you have installed everthing correctly, you will have to deal with little to nothing. For pnuematic guns, you might have a few more valves and moving parts, but not nearlly as many as electric airsoft guns or even gas airsoft guns!  Meaning, for these mechanical versions, you can even use them confidently in the rain or in wet conditions!
  • Quieter - The "noise" we get from airsoft guns are from their mechanisms working. For electric AEGs, thats the sound of the gears, piston, and cylinders moving to produce the necessary air pressure for the BB to be fired. For gas guns like GBBRs, the sound will be from the bolt carrier group, trigger, and expansion of gases in the gun. In spite of the fact that HPA guns are the most powerful type of airsoft gun, they are also among the quietest. As the only thing needed to propel the BB downrange is the necessary air pressure that will build up in its expansion chamber before its subsequently released, firing the BB. The sound produced will only be from the BB exiting the barrel and you can even use airsoft suppressors to further dampen this sound. This additional stealth can be especially beneficial if you are sniping and don't want to give away your position.

Drawbacks of HPA Guns

  • Weight - If you run a traditional HPA set up, which includes an external tank and line, the external canisters of pressurized air that attach to HPA guns are quite bulky and will increase the weight of the load you will need to carry on your person by a substantial amount. Though, there are different technologies from companies like Wolverine Airsoft that offer a system that uses Co2 capsules, you will still need to carry around the extra weight of all the capsules for your use on the field. Another work around is to use a set up that allows you to directly screw on a smaller tank to the back of your gun and use it as your buffer tube and stock. While this will decrease your personal load, it will put extra weight on the gun itself.
  • Cost - On average, an HPA set up will be more expensive than buying others such as AEGs or GBBRs. This is due to the fact that many popular HPA systems require a doner gun before you can turn it into a dedicated HPA airsoft gun. Alternatively, Wolverine Airsoft has created the MTW or Modular Training Weapon that is an actual airsoft gun designed to be an HPA gun. However, you will still need to purchase the necessary inerntal engines to make it work. These factors contribute to making HPA airsoft guns a good bit more expensive than other types of airsoft guns. 
  • Safety - What FPS is good for airsoft? While high FPS certainly offers plenty of advantages, having a higher FPS also means that HPA airsoft guns can hurt more than others. Due to this fact, many airsoft fields do not allow players to use HPA guns, and even many that do may require you to lower the FPS of your gun beforehand. Using a gun that sends BBs out at blistering speeds also isn't likely to win you many friends on the opposing team. On a much more serious note, many countries have very specific legal power limites for airsoft guns. Violating these laws might even land you and the seller of these HPA airsoft guns in serious legal troubles.  
  • Aesthetics and Realism - One of the biggest draws of airsoft is the fact that the guns and gear look so realistic, and many airsoft players enjoy the realism of the sport as much as the action that it offers. Having a gun that features a bulky air tank attached or an air line that runs out of it takes away a lot of this realism. By the same token, the fact that HPA airsoft guns are able to fire at much faster rates than even real full-auto weapons once again detracts from the realism of the sport. 

Is HPA Worth It?

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So do the advantages of HPA guns make up for their drawbacks? Ultimately, the answer to this question comes down to a matter of personal preference. There's no doubt that the higher FPS, faster rate of fire, and improved reliability of HPA guns will give you an advantage in most airsoft engagements, particularly at longer ranges. However, this improved performance comes at the cost of a gun that is heavier, more expensive, and not as realistic looking. 

Perhaps the most important drawback of HPA guns to keep in mind, though, is the need to have the tanks filled with specialized equipment. With AEGs, you simply need to recharge your batteries. With Gas guns, you simply need to buy new green gas or Co2 capsules. However, with HPA, you need an air compressor in order to fill your tanks. Chances of you having one of these at home is quite small, making you need to go to specialized stores or sites in order to refill your tank.

Secondly, oftentimes, they are seen as somewhat of a pariah among many airsoft players. It's easy to understand why people don't enjoy getting shot with a gun that shoots BBs at painfully high speeds. Even if you aren't too concerned with how opposing players will feel about being shot by your HPA gun, keep in mind that you may not able to use your HPA gun at all on certain airsoft fields. On other fields, you may have to lower the gun's FPS, therefore eliminating the biggest advantages that it provides. 

If the fields you go to allow HPA guns and you don't mind the extra weight and expense, there's no denying that HPA guns can be a lot of fun to use. For those who value accuracy, reliability, and power above all else, HPA guns are hard to beat. 

Example of HPA Guns

At RedWold Airsoft, we offer a variety of high-quality HPA airsoft guns in addition to HPA conversion kits that will allow you to convert your existing AEG or gas-powered airsoft gun into an HPA gun. If you've decided that an HPA airsoft rifle, an HPA airsoft shotgun, or an HPA airsoft sniper is the right choice for you, be sure to check out these great HPA guns and conversion kits from our catalog: 

ASG Scorpion EVO3 A1 SMG

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The ASG Scorpion EVO3 is already widely considered one of the best airsoft SMGs on the market. In its base AEG form, it gives you near PTW (Professional Training Weapon) levels of performance in a tight, affordable package. This example we have here is supercharged by Wolverine Airsoft and features their Inferno Gen. 2 HPA engine. The gun comes standard with all its base features such as semi-auto, full-auto, and a programmable burst. It also combines all the aforementioned benefits of HPA into one gun, making it a great choice for players right out of the box!

Pros

  • Ready to go out of the Box
  • Works with Other ASG Scorpion EVO3 Accessories like Magazines
  • Programmable Burst Mode
  • Wolverine Airsoft Inferno Gen. 2 Engine Built-In

Cons

  • Short SMG Form Factor
  • Designed to Work Internally only with Wolverine Airsoft

Wolverine Airsoft HPA Systems Wraith Co2 Stock for Regular M4 Series

Wolverine Airsoft HPA Systems WRAITH Co2 Stock for Regular M4 Series
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To many airsoft players curious about HPA but not wanting to deal with a tank and line, the Wolverine Airsoft Wraith Co2 stock is the perfect compromise. This innovative product gives you all the benefits of HPA and transforms your M4's buffer tube into a housing system for Co2 capsules to which in turn powers the HPA engine of your choice. This is the best compromise for players that want to give HPA a try while not wanting to sacrifice as much realism. You would imagine this to be the best option, however, its only drawback is you only get a limited amount of shots with Co2 and you will need to carry extra capsules to swap out on the field, potentially during gameplay.

Pros

  • Provides the Most Realism
  • Easy to Operate
  • Runs on Co2
  • Works with Standard Airsoft M4 Stocks

Cons

  • Only Designed for M4 Series
  • Limited Amount of Shots before Needing to Change Capsules

Wolverine Airsoft Bolt Sniper Rifle HPA Conversion kit

Wolverine Airsoft BOLT Sniper Rifle HPA Conversion Kit with Tokyo Marui VSR-10 Cylinder
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This is probably the best thing you can do for your bolt action sniper rifle. Designed to work with the Tokyo Marui VSR-10, the Wolverine Airsoft BOLT sniper conversion kit instantly turns your VSR-10 into a long-range, pin-point accurate precision rifle the likes many have not seen before. The biggest advantages you will see from this kit are the increased FPS offered using HPA and the consistency of the FPS output. Combined with the removal of any cylinder spring, the action you will feel from this is like playing a video game. The extremely silent shooting of this gun will catch any opponent off guard and easily give you the tactical advantage!

Pros

  • Increased FPS
  • Boosts FPS Consistency
  • Eliminates any Resistance in Pulling Back the Cylinder
  • Extremely Quiet Shooting

Cons

  • Requires a Doner VSR-10
  • Needs Hop-Up Upgrade for Maximum Performance