Every shooter since 1989 has wanted a submachine gun. Why?
Die Hard, that’s why. Bruce Willis ruined every single one of us (along with Hans Gruber). He also made the Model 92 super cool, but that’s a different article for a different time. We all wanted a 9mm sub-gun because that MP-5 was so sweet. Light, nimble, compact, and styling, the MP-5 has it all. Unfortunately, it also has a hefty H&K price tag attached.
Thankfully, the AR-15 is the most adaptable personal weapon platform in the history of mankind and is easily adapted to dozens of different calibers. One of the more popular variants is the AR-9, a 9x19 carbine that shares all common fire control group components but has a smaller lower receiver for 9mm magazines.
Early Varients of the 9mm AR-15
Contrary to popular belief, the 9mm AR-pattern carbine is nothing new; it has been around for decades. It was just never all that accessible or affordable until now.
The first widely available model was the Colt 6951. It used a stick magazine with a capacity of 32, and the lower receiver was a standard AR-15 with a magazine adapter. The upper receiver operated as a standard blowback rather than using the direct impingement standard for AR-15 rifles.
The 6951 was a variant of the Colt SMG, or Model 635, a select-fire SMG equipped with a 10.5” barrel. Introduced in 1982, it was a direct competitor to the MP-5. While sharing common components and being identical in operation, the Colt SMG never found the same favor as the MP-5 or the Uzi, for that matter.
What is a Pistol Caliber Carbine?
Put simply; a pistol caliber carbine is a carbine that is either designed or adapted to use pistol calibers.
These have had limited popularity over the years. You could correctly surmise that they were a novelty until manufacturers started slapping Glock magazines into them.
Then they exploded.
Pistol Caliber Carbine Uses/Advantages
So, there wasn’t much advantage tactically to using a pistol caliber carbine if you had to carry magazines that weren’t compatible with your sidearm.
It’s the same caliber. Great. So what? Are you supposed to dump the mags and put the ammo in your sidearm empties?
If the mags aren’t compatible, you might as well just pack a lot more punch with a 5.56 AR-15. Glock-mag compatible lowers started showing up everywhere. Magpul started producing high-cap Glock mags for dirt cheap, and it was game. Others got in the game, like Amend2.
Suddenly shooters realized that a pistol caliber carbine is a pretty sweet setup.
9x19mm ammo is still cheaper than .223/5.56, so it makes sense for basic skills training and short-range marksmanship training. Also, it gives you a carbine option for handgun-only ranges.
Pistol caliber carbines have plenty of power to dispatch farmyard predators (coyotes, raccoons, etc.), and a 16” barrel provides lots of reach.
While a 5.56 AR-15 doesn’t have much felt recoil, pistol caliber carbines have far less. As a result, they are a great home defense option for small-statured shooters, young shooters, and anyone.
Also, let’s have some real talk for a second: if you crack off a few 5.56 rounds in an enclosed structure, i.e., a living room or bedroom, you will be deaf for a while. Good luck communicating with the police when they show up. The 9mm is much more manageable indoors, where its concussive blast is far less jarring than a rifle caliber.
There are pistol caliber carbines in the most popular auto-loading calibers, but we’ll focus on the most common.
The 9mm Parabellum is the most popular pistol caliber carbine by a mile. The 9mm generally enjoys a significant resurgence in personal and professional use, with the big-bore calibers being largely abandoned. In addition, modern ammunition research and technologies have made the 9mm an effective caliber.
Take this with the wide availability of Glock magazines and the availability of inexpensive Glocks and Glock clones, and you have the making a dynamic duo. Like we said earlier, pistol caliber carbines never really took off. You had a handful of examples (Beretta CX4, Colt 6951, etc.), but these never took off.
You can now easily get an AR-9 carbine or pistol at un-Colt prices.
There are a few manufacturers of AR-pattern .40 S&W carbines, but the market for the once-dominating .40 has been slipping in recent years. The G17/19 and Sig P320 have taken the market over, and the .40 just isn’t what it used to be.
The good thing about a Glock-compatible lower is that it will take G22/23 mags since they are dimensionally identical to G17/19 mags. You can share a similar lower if you can find a .40 S&W upper.
Carbines and SMGs are a natural fit for the .45 ACP; it’s been happening since the 1920s with the Thompson SMG. This fearsome weapon cut its teeth on the roaring streets of prohibition-era America, but it came into its own in World War II, Korea, and Vietnam.
The .45 ACP remains an effective caliber when size matters. However, the ballistic advantage from a longer barrel is minimal for pistol calibers; the advantage lies in rapid follow-up shots and a much more stable platform. [To learn more, check out our guides to 45 ACP and 45 ACP vs. 9mm]
Ballistics/Effective Range of Pistol Caliber Carbines
First, a caveat: ballistics vary widely depending on case pressures, bullet weight, and even brand.
Second, ballistics for pistol calibers are universally tested and marketed with pistol-length barrels.
Without specific examples, we can conclude through a little Kentucky windage that the effective range will be somewhat better in a pistol carbine than in a pistol. Still, it won’t suddenly turn a 9mm into a 500-meter caliber.
Realistically, pistol caliber carbines will operate best in 100 yards and under distances. It is a close-range caliber, which is why it was so popular in the MP-5 with special forces military and police response teams; their fighting was largely urban.
If you know your shooting will regularly reach to and past 100 yards, grab yourself a standard AR-15. We’ve cracked the code on manufacturing ridiculously accurate rifles at low prices, so you should add one (or several) to your arsenal.
Should You Buy One?
In a word, yes. Especially if you own a Glock 9mm or one of the clones on the market, what’s the downside?
A 9mm AR uses common mags while preserving all of the operational elements of your AR-15 or AR-10. From the perspective of personal defense, it gives you all of the benefits of a pistol caliber in a more accurate and stable platform. In addition, you can mount any full-size optics on an AR-9 and full-size tactical flashlights.
Be sure to check out our BC-9 series of bufferless rifles and pistols. They are Glock-magazine compatible and give you an easy option for folding stocks or no stock if you want.
We believe a pistol caliber carbine is an excellent tool in your toolbox. It is cheaper for training while providing better range and power than a rimfire, but it still has plenty of power for self-defense and predator control on the farm and ranch. So pick one up today and find out for yourself!