… BEFORE I bought one! Welcome to my AR-9 Beginner Guide!
The AR-9 is fun. It has all the familiar controls of an AR-15 and shoots bullets that are about 1/2 the price of a 5.56 NATO round. So this means you can have more fun at the range for less pain in the pocket.
However, because there’s no mil-spec for the AR-9, it’s basically the wild west. Some guns work well, many do not. God forbid you try to slap multiple different components from multiple manufacturers together and expect things to work properly — good luck. Not all AR-9’s will properly feed JHPs rendering them sub-optimal for home defence or PDW purposes. And I haven’t even gotten to the best part, out of battery discharges aka kabooms.
I initially paid $833 for the gun you see above, but it took me another $1200 and a couple months to get it working properly. Thankfully, I think the gun is pretty sweet and it works flawlessly (finally).
| Part | Note | |
|---|---|---|
| Original Brigade BM-9 | $833 | |
| CMC Trigger | $165 | Single stage |
| Macon 9mm Builder’s kit – barrel, bolt, buffer | $366 | 5.5″ barrel |
| Brigand Arms Hoplite EDGE handguard | $207 | Low-profile |
| SBA3 Brace | $131 | |
| Just Right Carbines 8.5″ buffer tube | $40 | Testing recoil management |
| Kynshot RB5007 + red spring | $139 | Testing recoil management |
| Kynshot spacers | $41 | Testing recoil management |
| Radian Raptor SD | $100 | |
| Total | $2,022 |
The AR-9 has the following issues:
- Feeding issues with the barrel
- Bolt bounce leading to out of battery discharge / detonation / kaboom
- Premature primer strikes before chambering
- Cycling issues
Let’s walk through each issue and I’ll share with you what you need to do to alleviate or mitigate each problem that I encountered.
Barrel Feed Issues
Unfortunately, the above picture is a common sight for a lot of AR-9 owners when they try to use anything except for round-nosed FMJ rounds. in fact, the manufacturer of my original gun, Brigade Manufacturing, told me that they only tested the gun with FMJ!
The problem is with the feed cone of the barrel. The old Colt-style barrels were only designed to feed FMJ. Here’s a picture comparing the old style to the newer style:
Photo credit: Blowback9.com
As you can see on the right, the feed cone is much wider and much deeper. This allows for proper feeding of more flat-nosed defensive JHP rounds. There are a handful of manufactures making proper AR-9 barrels. Here’s a list of them:
Macon Armory (this is the one I have)
Aero Precision
Ballistic Advantage
Buffer Type
You want to make sure you have a Deadblow buffer. A Deadblow buffer is not a solid buffer, it has weights inside. So when you shake the buffer side-to-side, you will hear the weights move around inside.
A Deadblow buffer will not only reduce felt recoil, but in combination with the proper weight bolt (more on that in a minute), will reduce or eliminate bolt bounce. This is a good thing if you fancy a weapon that doesn’t go kaboom on you
Here are some good Deadblow buffers to consider:
Macon Armory Deadblow Buffer
KAK Industry Buffer
What about Hydraulic Buffers?
Hydraulic buffers are also a popular option that, in theory, addresses the same issues that the Deadblow buffer does. I say “in theory” because I haven’t actually gotten one to work reliably and consistently in my build. When it works, it’s soft shooting, but regardless of how much time and effort I have put into trying to get mine to work, it just will not cycle properly with heavier grain ammo.
I’ve tried:
standard length buffer tube + regular spring + hydraulic
standard length buffer tube + red spring + hydraulic
extended length buffer tube + regular spring + hydraulic
None of the above worked reliably.
Bolt Type
The bolt on an AR-9 is pretty simple compared to an AR-15. Simple and heavy. More on that below. What you need to be aware of with the bolt is this bottom feed lug piece I am pointing at in the picture to your right. This lug prevents the firing pin from coming into contact with the round before it’s fully chambered in the barrel.
There are some manufacturers that product bolts without this feed lug.
This can provide a bad time. You don’t want to have a bad time.
Buffer + Bolt Mass
The combined mass of the buffer ands bolt need to be between 22-24oz in weight. This will help to eliminate cycling issues.
Recommendations
I said it before and I’ll say it again… the AR-9 is a cool gun. It’s fun as hell, relatively cheap to operate, has the same familiar controls as an AR-15, has unlimited modifications possible, and is a superior home defense tool versus a handgun chambered in 9mm. But they’re prone to issues. Thankfully, there are a lot of people who really love this platform and fantastic places to learn about the platform with other fanatics ready and willing to share the results of their experiments. I recommend starting at the following places to nerd out on AR-9s:
Now on to my recommendations.
Build a proper AR-9 from scratch
if you’re a builder and a tinkerer, you’re going to have a lot of fun in the AR-9 world. Don’t do what I did though and buy one off the shelf that wasn’t built properly. Start properly and build one with known-compatible parts that have been proven to interoperate by the community. On my next build, I am going to build this gun listed to the right.
Blowback9 has an even better and more comprehensive list available on his site.
Reddit is also a great place to check out builds and build lists.
$1271 isn’t cheap, but it’s not MP5 / SP5 money. Of course, it’s not an MP5 / SP5, but it basically accomplishes the same task.
| Part | Price |
|---|---|
| Spike’s lower | $161.00 |
| Assembled upper (w/ LRBHO) | $80.00 |
| Brigand carbonfiber handguard | $207.41 |
| Lower parts kit | $60.00 |
| CMC Trigger | $165.00 |
| Macon 9mm Builder’s kit – barrel, bolt, buffer | $366.99 |
| SBA4 Brace | $131.00 |
| Radian Raptor SD | $100.00 |
| Total | $1,271.40 |
Buy a proper AR-9
My only recommendation here is the CMMG Banshee 9mm since it’s the only other AR-9 I have. It’s technically not a blowback operating system and works on their Radial Delayed Blowback system (RDB). The RDB works more like an AR-15 BCG and, as a result, is lighter and easier to operate because it doesn’t rely only on mass.
My CMMG has been flawless as soon as I passed 100 rounds. I had a slight trigger reset stick issue but that’s a known issue and it resolved itself as expected after breaking it in. I’m approaching 1000 rounds on it and it just works.
To be fair, I’m sure there are other properly-built AR-9s out there. Now that you know what to look for, you can ask the right questions and do the proper research and not waste time and money like I did.
Buy or Build a 300 Blackout
My best recommendation for a home defense weapon is to just skip the AR-9 altogether and buy or build a 300 blk. “Why?!”, you ask. Let me explain.
- 300 blk Subsonic suppressed is movie-quiet and packs a heavier punch than a 9mm
- With the right rounds, over-penetration shouldn’t be an issue
- 300 blk runs on the exact-same mil-spec platform as the AR-15 meaning it’s reliable
- With a quick swap of the magazine you can shoot supersonic rounds and get out to 200 yards and hunt if you wanted
- Price is basically on-par
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