The AR-9, a modification of the AR-15 platform which allows it to shoot pistol caliber cartridges, is one of the most popular firearms on the market today. But what exactly is an AR-9? Is it a complete carbon copy of the AR-15? There are a few nuances to the AR 9mm that make it very different from each other. In fact, the AR-9 has a completely different system for shooting than the AR-15, as it does not utilize a gas system.
Pistol calibers are typically shot out of handguns which are typically too small to reasonably fit a gas system, even on a miniature scale, that a rifle might have. Because many of the calibers we see in pistol cartridges are specifically designed around a particular model, they actually work better in systems that don’t utilize built up gas to cycle the action. Instead, pistol calibers are primarily designed with a blowback system.
What is a blowback system?
These systems are characterized by the fact that they do not utilize expanding gasses to cycle, but rather, the force of the expanding gasses to pull the action back. Any semi auto handgun will likely use this function unless it is an AR-15 pistol, or made from a platform with a different system.
The AR-9 shoots the 9mm cartridge, and while the AR-15 is able to shoot higher powered pistol cartridges, the AR-9 excels in shooting all pistol cartridges with a high level accuracy, primarily due to its firing system. Not only that, but because the AR-9 is essentially an AR, giving it all of the perks of the standard AR-15.
What Caliber is the AR-9?
The standard cartridge of the AR-9 is the 9mm luger cartridge. This was done on purpose as the AR-9 was initially designed for pistol cartridges while using Glock magazines. Essentially, the AR-9 is purely a commercial build, meaning it was never designed to be a battle implement. The 9mm cartridge especially in the 2000s when the AR-9 started to gain traction, it was only a matter of time before the AR platform and the 9mm Luger cartridge merged.
In order for the AR platform to work out properly with such a low powered cartridge, the fundamental system governing the cycling of the action had to be changed. The gas system that we normally see in an AR-15 does not work as well with the 9mm cartridge, because not enough of the expanding gasses will pass through the gas tube in order to cycle the action. Essentially, the problem is that the system will constantly be undergassed.
The solution to the caliber merger into the AR platform was fixed pretty early on in the development of the rifle. It was a rather simple decision that involved heading back to the roots of the semi automatic systems that are found in most handguns: The blowback system. In this system, there are much fewer parts meaning the system requires less energy. The bolt is also closed, as the bolt and the carrier are one. This updated design made the platform suitable for pistol cartridges, especially when fired through barrels under 7 inches.
While the AR-9 is based on the AR platform, it does not have the same level of modularity when it comes to the kinds of cartridges it can take as compared to the AR-15 or AR-10. The AR-9 is tailor made for the 9mm luger cartridge, and would only be suitable for .45 ACP otherwise.
Is the AR-9 Legal?
The AR-9 can either be a rifle, rifle carbine, or a pistol. Rifle carbines and rifles are viewed the same, but because of their different barrel lengths, produce different ballistic effects in comparison to each other. The AR-9 pistol is much like the AR-15 pistol in that it is an AR-9 made to fit the legal requirements of a pistol as defined in the National Firearms Act of 1934, as well as other ATF rules. The ATF is the federal body governing the laws of firearms, from ownership to the legal definitions of different types of firearms.
If an AR-9 is meant to be a rifle or a pistol, then it must have all of the criteria and follow all of the ATF rules regarding it. In this instance, an AR-9 pistol could not be equipped with a vertical foregrip, a barrel longer than 10” and an adjustable buttstock. However, AR-9 angled foregrips are allowed, as well as any barrel length that does not exceed 10.” AR-9 pistol braces are the most widely sought after buffer device as they are the most comfortable when shouldering.
Is the AR-9 pistol Reliable?
The AR-9 is truly a good firearm. Because its system is designed for pistol cartridges, it makes use of the finer qualities of most handgun systems while retraining the handling and performance of the AR-15. Out of this combination is a firearm that has great handling, reduced recoil, and amazing accuracy. On top of that, the AR-9 is very customizable, one of the many perks of the AR-15 platform. Being made from roughly the same materials, the AR-9 retains a lightweight yet durable build, and because it shoots much lore powered cartridges, is capable of a longer service life than even the AR-15 on its best day.
AR-9s make excellent competition guns. The 9mm cartridge is a very versatile cartridge, and although many would suggest that the 9mm is not very good with accuracy in longer barrels, it performs exceptionally well in the AR-9. This has to do with the standard twist rate and general control that a rifle has over most handguns.
AR-9 Parts List
The AR-9 is made of a few key systems that work together in order to create a fully functioning firearm. While simply made, there are many upgrades to this platform on that aftermarket that tweak these components, offering a little more complexity for those with the know-how to take advantage of. Here is a list and descriptions of all of the standard components that make an AR-9 work.
The AR-9 upper Assembly
The AR-9 upper is held together by the upper receiver, much like an AR-15. In this way, it functions much like an AR-15 except for the lack of a gas system. Here are the parts of the AR-9 upper
The Upper Receiver: The upper receiver is the housing component for all the major parts of the AR-9 upper. From this part, all other pieces are either connected or function with the parts housed in it.
The Bolt: The bolt for the AR-9 upper is chambered for the 9mm cartridge. It is not an open bolt system meaning that the bolt and the carrier are one piece, much like the slide on a Glock, where the firing pin is inside. The bolt is made for rimless cartridges.
The barrel: The barrel of an AR-9 is not unique compared to the AR-15 as it is designed as a free float system. The free float system is connected to the upper receiver, and has no other parts touching the barrel. This greatly increases barrel.
Charging Handle: The charging handle is one thing that the AR-9 kept from the original AR-15 design. This tool is utilized to pull the bolt back in order to “charge” the system with the first cartridge.
Handguard: Because the barrel is free floating on an AR-9, that means it must have a handguard that accommodates its function. Handguards will often be free floating as well, made either for the keymod or MLOK mounting system.
Muzzle devices: There are a series of different muzzle devices made for the AR-9. Among the most common muzzle devices is the flash hider, which sufficiently suppresses the flash of the bullet as it is exiting. Normally this is needed on rifle cartridges, as not all of the powder is burnt up inside the barrel.
The AR-9 Lower Assembly
The AR-9 Lower houses the lower components, including the fire control group. This system works hand in hand with the upper in order to make the gun function.
AR-9 lower receiver: The AR-9 Lower receiver is the housing component for all of the lower parts. This holds the grip, the fire control group, and the buffer system.
The fire control group: The fire control group is the main system held in the lower receiver. It is also one of the only parts of the AR-9 that is exactly the same as the AR-15. Any mil spec AR-15 trigger system will work in a mil spec AR-9 lower receiver. Included in the fire control group are the trigger, hammer, safety selector, and bolt catch.
The grip: The grip of an AR-9 is much like that of an AR-15 as well. However, it is one of the easiest parts on the AR-9 to upgrade as it is only held in by a threaded screw. Magpul grips are among the most commonly upgraded grips you can buy for the AR-9.
Buffer System: The buffer system is a system consisting of a weight and a spring, which are responsible for pushing the bolt back into the battery. The buffer system also carries a dual function as it also alleviates some of the recoil on the shoulder when the gun is fired.
Butt stock: The buttstock on a carbine rifle like the AR-9 resembles heavily the adjustable stock on an AR-15. Like the grip, magpul buttstocks are often the most commonly sought after in terms of cheap upgrades.
How to Build an AR-9 pistol?
The AR-9 is much like the AR-15 in regards to the tools required to build one. Whether its from an 80% lower receiver, or a completely stripped lower, many of the processes are the same because they work from the same platform. The main difference between building an AR-9 vs an AR-15 is that the AR-9 does not have a gas system and therefore does not require the installation of the gas tube or gas block.
How to build an 80% lower AR-9
In order to begin building an AR-9 using an 80% lower, you will need the following tools:
- Jig kit
- Hand drill/ router/ Drill press/ CNC Machine
- Armorers wrench
- Roll pin punch set and hammer
Once all of the tools are gathered, the machining process will commence. This is the most critical part of the build process and relies on the jig kit to properly outline the measurements for the millining locations.
Once the machining process is done, the receiver becomes a legal firearm and must be treated as such. At this time, the assembly process will begin where the installation of the fire control group, magazine release, and buffer will take place.
The testing phase ensures a safe assembly. It is important to understand the functionality of all the parts in this phase in order to gauge if everything is working properly. Oftentimes people run into issues with the build process when there is a lack of oversight. Once the assembly process is done, make sure to take some time to check if everything has been done properly before attempting to shoot the new AR-9.
The process for building an AR-9 with complete stripped lower is much the same, except there will be no need for the milling process. The stripped lower is considered a firearm because it has the trigger milled out already, and while it makes the building process a little more convenient, stripped lowers must go through the same purchase process as regular firearms.
How Hard is it to build an AR-9 pistol?
AR-9s, being of the same family as the AR-15, are not hard at all to build. In fact, they are a tad easier to build than the AR-15 because you don’t have to worry about installing a gas system properly. Oftentimes, the gas system on any pre-built upper assembly will need to be tweaked, especially depending on the type of ammo being used. In the case of the AR-9, that is one less step during the building process.
If you are building an AR-9 from an 80% lower, the procedure is exactly the same. That is because the AR-9 uses the same lower parts kit as the AR-15. The main difference in the trigger group of an AR-9 compared to the AR-15 is the magazine release which must be made for glock magazines as is typical with most AR-9 lower receivers. Building an 80% lower AR-9 requires a jig kit and either a drill press or a router jig in order to be milled properly.
Should you buy or build an AR-9 pistol?
When building an AR-9, you might notice very early on that the price of a build versus the price of one already completed is very similar. That is because the AR-9 platform itself is headed by a series of aftermarket companies making parts for it. Since the AR-9 is essentially an aftermarket version of the AR-15, the price of an AR-9 will be the same or similar from company to company. There are some advantages to building that buying does not have, provided a small skill curve is hurdled over beforehand.
Especially when building an AR-9 from an 80% lower receiver, the process is very much the same, but is also cheaper, because there are no background check fees or transfer fees to worry about. In this case, you can even have the AR-9 80% lower build kit sent directly to your house.
Is the AR-9 pistol worth it?
While AR-9s are much like the AR-15s out there in the market, they do not share the same cost effectiveness. In the market, it is much easier and cheaper to buy an AR-15 than it is to buy an AR-9. The price of the AR-9 commonly in the market is around $700, so in comparison to other guns that shoot the same caliber, it is a viable option. However, when it comes to either building one or buying one, there is not really a difference in price.
The main reason to buy an AR-9 is primarily for its accuracy, durability, and handling. While they might not be the most inexpensive guns out there, they rely on a cheap round, the 9mm, which can be purchased as range ammo or self defense. Essentially,the AR-9 is even more capable for self defense than the AR-9, especially in the home, as the AR-9 is not as high-powered, and therefore not as much of a threat to others in the household. The AR-9 plays its role as a plinker and a self defense tool much more seamlessly than the AR-15, and is capable of the same if not better modifications.
The AR-9 is a versatile rifle despite its short term in the market, since 2004. Although attempts were made by the commercial market to make the firearm a standard, the aftermarket eventually took hold of it, causing the platform to skyrocket in terms of modularity and popularity. The AR-9 we know today, responds to many of the issues found by the top brands, and is almost entirely community developed.
It utilizes a cheap cartridge, great for the range or for self defense in a system with low recoil and great handling. Its parts are much more similar to the AR-15, making it something easy to get into if you are familiar with that platform. It is a great beginner shooter as well because of its low recoil and simplistic design. While the AR-9 might not be the most inexpensive gun out there, there are still ways to make it a bit cheaper by opting to build one from an 80% lower receiver.
The AR-9 is a great self defense tool, utilizing one of the cheapest most accessible cartridges: the 9mm luger. The cartridge has very many options for self defense, like hollow points and increased grains for greater stopping power.
The AR-9 is made from the AR platform, meaning it can be built in a DIY format using an 80% lower or a completely stripped lower. This enables buyers to formulate a more in depth budget where they can gauge the amount they want to spend on a variety of the parts the platform needs to function.
The AR-9 can be purchased on online gun stores across the web. With a variety of brand name and aftermarket parts, there is a wide range of prices that buyers can base their budgets off of to have a unique AR-9.
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