If you’re basing the home defense argument on stopping power and lethality, you’re never going to win the argument with a pistol caliber. But alas, the argument in its fullness is not simply about stopping power and lethality.
Certain home defense needs can readily and sufficiently be met with pistol caliber AR builds. And most of the time a dedicated AR built for that caliber provides the type of reliability and proven effectiveness in operation that the AR is famous for. This, despite a mixed history of early success and failure in converting the AR to a pistol centric system.
This article will talk about the benefits and drawbacks of the pistol calibers and how they might be best used in a home defense setup on the AR platform. It’s not a perfect solution, but it is infinitely customizable, very approachable, easy to handle and familiar to many shooters. It is also a vehicle for harnessing high capacities, muscle memory and components you may already have in your possession, thanks to the utility and wide availability of the modular AR platform.
Best Pistol Caliber ARs
Choosing a pistol caliber AR can be difficult. That is where we come in. Below you will find our choices of some of the best options for your home defense needs. We also have provided a rundown of calibers available and things to consider while shopping.
1. Sig Sauer MPX 9mm PCC
While these pistol caliber carbines are not in order of best to worst, this is my favorite on the list. Sig makes great guns, and their MPX line is no different.
Deciding between this and the next option on the list can be difficult as the main difference is the barrel length. Get what will work best for you and your home, as well as your state laws.
Both the MPX and the MPX K come with great triggers and furniture. You know you are getting the great quality from Sig Sauer.
2. Sig Sauer MPX K
Just like with the firearm listed above, the MPX K comes with a great trigger. You get most of the same great features as the longer MPX.
One advantage this version offers is the shorter barrel. This comes in handy for CQB and clearing rooms.
The folding stock is also a great feature for a small pistol caliber carbine as it allows you to store it in small areas like a backpack.
3. CZ Scorpion EVO 3 S1
The CZ Scorpion EVO 3 S1 is a great option if you are looking for a high performing carbine rifle chambered in 9mm. This rifle is compact and lightweight making it a great choice for home defense.
It is a blowback operated semi-auto pistol that features a monolithic upper receiver and a 16-inch barrel with a faux suppressor.
This firearm is easy to configure and operate with its ambidextrous controls. It is very easy to add optics and other equipment to help improve your shooting.
4. Kel-Tec Sub-2000 G2
This firearm is a semi-automatic rifle chambered for the 9mm that is budget-friendly and versatile for the user. The stock can be adjusted for the shooter’s comfort. Each position adds approximately 5/8 of an inch to the overall length of the weapon.
An advantage to this rifle is that it has multiple pistol magazine options. It is compatible with Glock 19/17, 23/22, Beretta 92/96, Sig P226, and the S&W M&P magazines.
It is a simple and reliable firearm that folds and stows nicely for easy convenience. Because of its 16″ barrel you’ll get the most out of your ammunition.
5. Ruger PC Carbine 9mm
The Ruger PC Carbine 9mm is a durable and reliable firearm. It doesn’t malfunction very often and is reasonably accurate with iron sights. It is rather quiet when using the right silencer and ammunition.
It features a barrel mounted picatinny rail for forward mounting of optics and a rear picatinny rail for the mounting of standard AR grips.
This firearm comes with an ergonomic pistol grip that provides an extended trigger reach for better trigger control.
6. CMMG Banshee 300 MkGs
The CMMG Banshee 300 MkGs is chambered in 9mm and is compatible with the Glock magazines. The barrel is made extremely durable with 4140 steel and a salt bath Nitride finish. It is compact and lightweight which makes it great for home defense.
The Banchee 300 series is the premium choice for these firearms. It has a lot of features and options that the 100 and 200 series don’t.
This firearm is very reliable and little maintenance is required. It is ergonomically sound with a well thought out magazine release and lots of ambidextrous controls.
Why Choose A Pistol Caliber Carbine?
The argument FOR the pistol caliber AR as a real-world solution for home defense:
- Pistol cartridges offer proven stopping power (think CCW’s and duty weapons for Law Enforcement) but very manageable recoil in larger sized guns (think larger pistols and carbines that the AR is well suited to)
- Easy crossover availability to cartridges may eliminate the need to stock another round type or may have some ancillary cost savings. Many pistol cartridges offer significant cost savings over rifle cartridges.
- The AR platform in the past 10 years has been proven reliable with many pistol cartridges.
- Overpenetration can be easier to mitigate with certain calibers, when compared to high powered cartridges out of a centerfire rifle.
- Pistol caliber builds might be an easier package to handle than a larger rifle cartridge-based AR build.
- In the case of a rifle build, you can get an easy recoiling firearm that is shoulder able for better aim, and a gun that is harder to remove from you by an aggressive threat.
- Pistol cartridges are generally optimized for shorter barrels which means you may be able to find adequate ballistic performance out of a much shorter overall length system enhancing mobility and turning radius in a typical residential environment.
Building a dedicated pistol caliber AR is also a very good reason to throw some money at a build when you cannot think of another way to spend your cash. But are they really that good for home defense? Do they function in some hybrid fashion, or are they just an overhyped, misunderstood, or over-marketed option?
The argument AGAINST the pistol caliber AR as a real-world solution for home defense:
- The AR is a rifle platform at its heart and the cartridge offering for that platform is continually embraced by military and law enforcement as a primary solution for tactical scenarios.
- A rifle cartridge has enhanced stopping power generally.
- Why spend the extra money for a dedicated solution, when so many good pistol platforms exist already? If you want a pistol, by a pistol.
- Reliability seems to have a complicated history when it comes to pistol cartridge-driven builds, and even if reliability is spectacular relative to historical data now, it may never be decoupled from the argument.
Let’s explore these concepts and see if some light can be shed on the topic of using an AR with a pistol caliber as the core component driver.
Things To Consider About Pistol Caliber Carbines
When it comes to AR’s in pistol calibers, it usually isn’t just an upper receiver drop-in. There are some one-off drop-in conversions, for instance, the very cool 5.7×28 which one could argue either way on the efficacy of the conversion for home defense usage (more on that below). That upper is a specialty upper that requires a different internal mechanism and a modified conversion magazine to run effectively. It is also not a natively reliable cartridge in the AR, generally. Other, shorter cartridges require dedicated builds, or a drop in upper to pair with a caliber specific lower build. That means that the cost factor and variability of the AR as a platform takes a negative hit when considering a pistol caliber as a first choice option.
Nevertheless, there are some compelling arguments to be made regarding the idea of the pistol caliber AR for defensive purposes inside of a home where the unique attributes of CQB are a primary factor for consideration.
Caliber Options For Pistol Carbine ARs
There is no shortage of pistol caliber options – but for many of these cartridges on the AR platform, it has been a novelty run for many years until the reemergence of the 9mm as top dog on the law enforcement landscape, and its ability to be nearly flawless in most of the historical pistol based designs on the AR clone scene.
Now, it seems that every manufacturer is serious about marketing the defensive attributes of a pistol caliber driven AR. Let’s see how much of it is marketing hype. And as a disclaimer: marketing hype doesn’t mean that pistol caliber AR’s are ONLY that.
There are many excellent use cases for pistol caliber AR builds across the spectrum of shooting tasks and recreational use cases. And as you’ll see, there is definitely a defensive application for certain users, if you weren’t already certain of that fact until now.
This is the most difficult caliber to assess in a black and white fashion for the question at hand. The 5.7x28mm is an incredible CQB cartridge. Everything about it was built for that essential task. The projectile is systematically designed to tumble after a first hit, in order to reduce second hit probability and provide intricate, hard to repair wound channels and mitigate ricochet.
It is built to be a high capacity cartridge that can easily be mag-fed in a variety of positions; while providing a lethal small caliber, easy to handle experience. It is a military and law enforcement darling, and it is blazingly fast, creates a very intricate and interesting wound profile; and it is proven to be very reliable in most systems that have adopted it.
But here’s the rub: while it may be a very considerable way to defend in a CQB scenario like a home defense situation, it is also a tiny grain weight that may not have immediate stopping power for single shot stopping needs. It is also not proven to be reliable on the AR the way that the 9mm is on the AR, or the 5.56/.223 is already. And why go for the 5.7×28, when you can natively use the .223/5.56 and have a superior firepower option with absolute reliability? It’s more expensive, less reliable, harder to guarantee low volume shot stopping power, etc., etc.
The options for uppers/magazines are minimal, though CMMG makes a very good representation of the components. The delayed blowback operation offers a different take on the AR than native builds. The magazine should not solely be the driver for reliability in the success of a caliber conversion, and the fact that it must be relied upon wholesale in the case of the conversion mag type, means that it has higher chance of failure than those custom-built lowers offering a single caliber.
That all said: it’s hard to find fault with such an interesting caliber, especially where second hit probabilities must be minimized as much as possible (other family in the home; high density living spaces like apartments, etc.). The fact that the engineering and proven performance of the projectile used in the 5.7 is designed to encourage a tumbling effect makes it interesting from an overall wound profile perspective and can help to minimize wall penetration too.
While it’s impossible to recommend this over a .223/5.56, it is a very interesting option for those who have the use cases that align with the 5.7x28mm.
Now that we have overwhelming evidence of the prowess of the 9mm luger and the various defensive loads, it’s hard to bet against it.
The single caveat is that there are still over penetration concerns along with less substantial stopping power comparatively to rifle rounds. The larger mass enjoys substantial penetration, with velocity that could still punch through the walls while a .223/5.56 is likely to tumble and change direction or lose significant velocity and direction after a first hit. Those statements aren’t stationary, absolute truths, but there are some engineering truths that tend to push performance that way in certain cases. The .223/5.56 can absolutely over penetrate and continue its flight path towards a risky location.
In defensive scenarios, only one truth exists: nothing is absolute.
Again, the argument becomes: why opt for a pistol caliber that has the same risks, without the enhanced stopping power, velocity, and terminal proven performance out of the platform. Well, the overarching concept is that the 9mm itself is also ridiculously proven. All 9mm loads are also easier to suppress for sound; can be dialed back to be subsonic and maintain excellent stopping power, and can be used in many different scenarios, so having a dedicated AR with a 9mm build style is not a bad concept.
Thanks to the blunt and overt size differences inherent to the .45 it is seen as a very effective self defense round where a second hit probability needs to be managed. It’s a larger diameter and creates excellent wound channels with usually sufficient penetration and can be effectively suppressed. The rise of dedicated platforms, like the Kriss Vector has also drawn a lot of attention to the caliber for defensive purposes. It also has a decent track record of performance on the AR platform.
It’s an option, certainly, but may not be as viable as the .300BLK if you prioritize suppressor usage and want reliable penetration and second hit probability decreases. In this case, it’s about as interesting as the 9mm for vastly different reasons.
The marketing champion for those that have the money. The 10mm got a lot of great press when it was touted as the hottest pistol caliber. A caliber so hot it basically “broke” the MP5 by HK, when the FBI tried to test a batch for implementation in the 1990’s. Some of that storyline is a bit overblown, but the recoil was not manageable in the submachine gun format for a lot of testing agents.
The 10mm is a fun round if you like velocity and penetration. Which is exactly why you wouldn’t pick a pistol caliber for an AR built exclusively for home defense. When you have such great rifle calibers like the 5.56/.223 and the 6.8SPC, and a plethora of others that offer superior firepower, you’d have to opt for the 10mm for the love of the game – not for practicality’s sake.
Less performance than the 10mm and the 9mm. But not all that bad, considering the more manageable recoil comparatively to both. The .40S&W feels less muzzle snappy than the 9mm, but recoils more straight-back, much like the .45ACP, and is much more realistic for repeat firing than the 10mm thanks to the muzzle snap of that cartridge too.
It was the Law Enforcement darling for years, until the 9mm seemed to outperform its real world datasets in the era of data science in law enforcement. It has taken a backseat to the 9mm now.
Here’s the familiar argument: why choose this, when there are better pistol cartridge options, not to mention the superior firepower of the rifle rounds for the AR?
AR Carbine Performance Numbers By Caliber
Pistol Caliber Carbine Performance Numbers
|5.7×28||23 gr||2800 fps||395 ft lbs|
|9mm||124 gr||1150 fps||365 ft lbs|
|.45 ACP||230 gr||835 fps||355 ft lbs|
|10mm||180 gr||1300 fps||705 ft lbs|
|.40 S&W||165 gr||1130 fps||465 ft lbs|
Rifle Caliber Carbine Performance Numbers (Home Defense Cartridges)
|5.56/.223||55 gr||3250 fps||1295 ft lbs|
|.300BLK Supersonic||125 gr||2210 fps||1350 ft lbs|
|.300BLK Subsonic||220 gr||1000 fps||495 ft lbs|
|6.8SPC||115 gr||2550 fps||1695 ft lbs|
|.308/7.62||175 gr||2600 fps||2615 ft lbs|
The numbers tell the tale. At least for performance. And with penetration issues already likely with most, you lose a lot of performance chasing an elusive hybrid option that may not be able to deliver.
Defensive Scenarios In General
Every single defensive scenario that exists serves only to prove that there are no constants in defensive scenarios.
Sure, there are some similarities and big data can prove that, but every single situation is unique and like a fingerprint. It has little anomalies that are based on personal chemical reaction in the brain and body, training, clarity, tools involved and about 100,000 other variables.
For you, a pistol caliber might make the most sense for a home defensive use case. But don’t let it be because you bought into the hype that you should give up stopping power for lesser threat mitigation. If you value stopping power, you use the AR with a rifle cartridge as the focal point for home defense.
That said, if you have a special case where using a pistol caliber or specific build of the AR around the pistol cartridge of your choice, we won’t try to convince you to ignore what your gut is telling you.
Objectively in almost every important metric, certain rifle cartridges will outperform pistol cartridges when it comes to the AR platform in CQB home based engagements. That is also true for penetration concerns – when addressed properly. And yes, rifle projectiles have over penetration and second shot probabilities through the roof compared to some pistol cartridges. But the data does show those things can be mitigated with proper planning and the right loads and projectile mixes.
The most important gun for you to use in defense of yourself, is the one you are most confident in, regarding your ability to stop a threat.
Size, Mobility, And Simplicity Of Pistol Caliber Uppers
The form factor of most dedicated pistol caliber builds on the AR are going to be perfect for CQB and the tight spaces of a normal tract home – where many readers (and probably a vast majority of readers) will reside, if not in apartments.
That’s part of the easy sale. It’s part of the staying power of the option. It’s part of the reason why a case can be made (as long as you trust the stopping power of the cartridge/load you utilize), for using a pistol-caliber-centric AR build for a home defense need.
Pistol Caliber Carbine Reliability
Lack of reliability is mostly a thing of the past when it comes to the current market offerings, though, admittedly, there are some causes for concern.
Making fundamental changes to the design and architecture of the proven AR platform to accommodate a pistol caliber will inherently change its reliability. Changing from a centerfire rifle cartridge to a centerfire pistol cartridge fundamentally changes how the springs and mechanisms react and move. This can introduce concerns, generally.
That doesn’t mean that newer models and brand releases are not reliable. They are, or they wouldn’t sell. But they haven’t been proven out for decades like other platforms and other cartridges on the AR platform specifically.
It only takes 1 failed shot to cause a problem.
Ultimately, it comes down to what you know about yourself, your capabilities, and your unique variables like, training, mobility needs, home footprint, friendly fire concerns, confidence in the cartridge of choice and many other pieces of information.
The bottom line: Make sure you are using the right tool to do the job, and make sure you have absolute confidence that you defended yourself “by the book” if it ever happens to be something you face in your home. Check out our article on the best insurance options to make sure you have yourself covered as well!
In the end you must choose wisely for your specific needs and hopefully you’ve been given a decent primer to prepare you to do so in this article.