How To Setup an AR9 Build For Home Defense

Posted by on Mar 21st 2023

How To Setup an AR9 Build For Home Defense

Originally posted here.

When it comes to protecting ourselves and our loved ones, our homes are our first line of defense.

Unfortunately, no one can predict when a home invasion or burglary will happen, which is why it’s crucial to be prepared for the worst-case scenario.

Having a home defense plan and the right equipment can make all the difference in protecting your family and property.

How To Setup an AR9 Build For Home Defense

Why an AR9 build is a good choice for Home Defense

One popular option for home defense is the AR9 build.

An AR9 is a variant of the popular AR platform that fires 9mm rounds, which are a great choice for indoor use because they have less recoil and a lower risk of over-penetration.

The AR9 has the same manual of arms as an AR15, so the transition between the two is seamless.

This blog post will provide an overview of how to set up an AR9 build for home defense.

It will cover the basics of an AR9 build, including the components needed and how to choose the right ones.

Planning an AR9 Build For Home Defense

Now that we have established the need for home defense, let’s explore the key factors to consider when planning an AR9 build.

Choosing the right Barrel Length

Although ammunition design, manufacturing, and testing have seen significant improvements over the years, shooting a pistol cartridge out of a 16" carbine-length barrel still provides a distinct ballistic advantage.


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Prices accurate at time of writing

Best Barrel Twist Rate For an AR9

Selecting the ideal twist rate for your AR9 is fortunately a straightforward task. Many handguns and rifles that are chambered in 9mm have already established that a 1:10 twist rate is optimal. Consequently, when the AR9 platform was introduced, manufacturers adopted the 1:10 twist rate as well.

Additionally, the 1:10 twist rate quickly expends most of the cartridge’s energy. With a twist rate of 1:10, you can use a wide range of ammunition loads. Keep in mind that if your AR9 encounters issues cycling or ejecting spent casings, a lighter buffer may be necessary.

Choosing the right Buffer

The buffer systems required for an AR9 build are actually the same type of buffer used in an AR-15, which is quite convenient.

Generally, a heavy “Rifle" or H3 buffer (weighing between 5.0 and 5.4 ounces) is preferred by most shooters for subsonic, suppressed 9mm loads.

However, if you pair a pistol buffer (weighing 8.5 ounces) with a standard AR-15 recoil spring and buffer tube, your AR9 should cycle and operate reliably for all types of loads.


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Choosing the right Magazines

Nowadays, the majority of AR9s and 9mm lower receivers are designed to be compatible with GLOCK magazines, although there are still some that can use Colt’s 9mm SMG magazines.

If you want to use GLOCK mags, you can opt for a G-9 Hybrid Bolt and a Glock-Compatible AR9 Lower.

It’s worth noting that most builders tend to prefer GLOCK magazines.


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Choosing the right Optics

On my personal AR9 build, I’m running an EOTech 512. I’ve used red dot optics in the past, but I’ve found the design of the EOTech 512 and the donut of death reticle work best for an AR9 set up for home defense.

If you’re looking for a sight that offers quick target acquisition, dependability, and toughness but doesn’t come with Night Vision features, the EOTech Model 512 could be just right for you. It can be mounted directly onto a Weaver or MIL-STD 1913 rail, and runs on 2 AA batteries (lithium, alkaline, or rechargeable) with a battery life of up to 1,000 hours (lithium) or 600 hours (alkaline) when used at a brightness level of 12.


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Prices accurate at time of writing

Choosing the right Weapon Light

On my personal build, I’m currently using the Princeton Tec Switch Rail weapon-mounted task light.

This light is specifically created for signature reduction, stealth structure search, and breaching operations. Its recessed LEDs offer discreet lighting in various specialty color combinations. It can be easily mounted onto a Picatinny Rail with the Switch Rail attachment, ensuring a secure fit. Additionally, a single button provides access to up to two constant lighting modes.


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If you’re in the market for a weapon light with more lumens and throw, then I would suggest the SureFire M140 Micro Scout Light Pro, which provides 300 Lumens of output.


$269.00 at Primary Arms VIEW DETAILS
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Choosing the right Ammunition

Lucky Gunner did some extensive testing with various 9mm loads from a Ruger PC 9mm carbine. They fired a variety of ammunition through the pistol caliber carbine, including defensive ammo.

What they found was that bullets in the 124-grain range reach great velocities but tend to expand early and penetrate less.

The heavier 147-grain rounds penetrated deeply and expanded consistently. Firing these rounds from a 16-inch barrel led to optimal performance.


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Additionally, the heavier 9mm rounds performed better at longer ranges, just outside of the typical home defense range. So if you need to create some stand-off distance or dispatch a varmint at ranges outside of 25 yards, an AR9 build with a 16" barrel and heavier 147-grain ammo will certainly do the trick.

RELATED -> Winchester Black Talon Bullets and Modern-Day Equivalents

If you don’t want to build an AR9 from the ground up, there are some great options on the market for a fully built AR9 platform. One of those options is the Faxon Bantam.

Faxon Firearms Bantam AR9 Complete Build

Looking to enter the PCC market? The Faxon Bantam 16" 9mm Pistol Caliber Carbine is an excellent choice.

As part of Faxon’s First Line, the Bantam Rifle is packed with features that provide great value for customers. The Bantam series offers upgrades typically found on pricier rifles at an affordable price point for the average American.


$1,049.00 at Faxon Firearms VIEW DETAILS
Prices accurate at time of writing

These rifles provide a solid foundation for future upgrades and feature Faxon’s renowned barrels, nitrided PCC BCG, enhanced forged receiver sets with a tensioning screw, and last-round bolt hold open. The free-floated M-LOK handguard is an added bonus.

With the Faxon Bantam, you’re getting a quality-built PCC with all the above specs. All you need to do is provide an optic and light.

READ NEXT -> 10 Best 9mm Carbine Options [2023]


The importance of having a well-prepared home defense strategy cannot be overstated. With the rising number of home invasions and burglaries, it is crucial to have a plan in place to keep your family and property safe.

A home defense system that includes an AR9 build can provide an effective and reliable option for defense against intruders.

An AR9 build has several advantages that make it an attractive option for home defense. It is a compact and lightweight firearm that is easy to handle, even in tight spaces. Its 9mm caliber also offers reduced recoil, making it more comfortable to shoot for novice shooters.

Additionally, the AR9’s compatibility with Glock magazines means you can take advantage of a widely available and reliable feeding system.