A carbine chambered in a pistol caliber like the 9mm means less recoil and muzzle blast, and more accurately placed bullets downrange on the target. Stag Arms’ semi-automatic Models 9 and 9T are designed specifically for 9mm ammunition—the same ammo you might carry in your sidearm—yet offer the familiarity of the AR platform.

Many AR manufacturers over the years have offered 9mm conversion kits to allow AR-15s to fire 9mm ammo. Typically, a 9mm upper is used with a drop-in magazine block to make the 5.56mm magazine well compatible with 9mm stick magazines. Stag Arms’ Models 9 and 9T, however, employ dedicated 9mm upper and lower receivers.

To The Nines

The uppers feature heavy-profile, 16-inch, 4140 steel barrels with 1-in-10-inch twist rates. The bore and chamber are chromed, and the muzzle is capped with an A2-style flash suppressor. As with all Stag Arms ARs, right- and left-handed configurations are available.

What also sets these 9mm ARs apart from standard AR-15s is the operating system. The Models 9 and 9T use a simple blowback system—not a direct impingement or gas piston system. The Stag upper employs a one-piece bolt and carrier with a modified ejection port cover and an enlarged brass deflector. The lower receiver is also different, as it uses an integrated magazine well plus a specially designed hammer, magazine catch and recoil buffer. All of the AR controls, including the safety, charging handle, magazine release, safety selector and forward assist, function the same.

The Models 9 and 9T accept standard 32-round, Colt-style, 9mm AR magazines—straight sticks holding a double-stack column of cartridges. The carbines come with magazines featuring steel bodies and polymer followers that are bright orange so a user can visibly see the magazine is unloaded when the bolt locks back after the last shot is fired. The magazines have round-count witness holes, and the steel floorplates slide out easily when the detent pin is pressed in for easy disassembly and maintenance. Brownells offers Colt-style magazines, so I ordered a few. They are constructed of steel with steel followers and a slick Xylan coating for smoother operation.

The Model 9 features an optic-ready, non-functioning, railed gas block and a Diamondhead VRS-T handguard. The Model 9T comes with a longer, free-floating, 13.5-inch Diamondhead VRS-T handguard as well as flip-up, aluminum Diamondhead sights. Both of the handguards are drilled and tapped at the 3, 6, and 9 o’clock positions so Picatinny rails can be added to attach lights, lasers and other accessories. Oblong cutouts along the sides and bottom of each handguard help reduce weight and ensure the barrel cools quickly. As mentioned, the Models 9 and 9T are also available in left-hand configurations.

Running The Stag

I got my hands on a Model 9T and found it was pure AR but with less recoil, less muzzle climb and less noise. For sighting I mounted a Mepro Tru-Dot RDS with a 1.8-MOA reticle. In handling the 9T, manipulating the stick magazine into the magazine well was the only thing that was different, since the magazine is long and skinny compared to the typical AR-15-style magazines that are wider and flatter.

Using 9mm ammunition offers less overpenetration, but most users know that choosing the right 5.56mm ammo can achieve similar results. But with a 9mm rifle, you can run it and a pistol with the same ammo. There’s no need to buy two types of ammo. I loaded the Stag Arms and Brownells magazines with Winchester’s 115-grain “White Box” FMJs, Hornady’s 115-grain Steel Match HAP rounds and Atlanta Arms’ 147-grain FMJs.

I had absolutely no issues running the Model 9T with either the Stag Arms or Brownells magazines. Even when I mixed up ammo types in a magazine, the Model 9T didn’t even come close to choking, and I ran it hard with numerous tactical and bolt-lock reloads as the extra packing lube cooked off due to the continuous shooting. The carbine ran flawlessly throughout my testing on the range.

The 9T uses a single-stage trigger, and my test sample’s pull weight averaged 5.9 pounds. It had a slightly perceptible amount of creep before it broke, but I liked the trigger and was able to rapidly reset and fire for accurate sustained bursts. Bench-resting the 9T, I was able to shoot some nice tight groups. My best five-shot group at 25 yards, produced with the Winchester ammo, measured 0.75 inches. Firing off-hand for speed, the groups opened up to about 4 inches on average at that distance with all the ammo tested. Loading one, two or three rounds in the four magazines and then mixing them up on the bench top allowed me to practice bolt-lock reloads with the sticks since I did not know how many rounds were in a magazine or when the bolt would lock back. This gave me the chance to become further acquainted with how the 9T operated, plus I was able to work the stick magazines more efficiently.

The Mepro Tru-Dot sight was fast on target. It suited the Stag Arms Model 9T well and also co-witnessed with the Diamondhead iron sights. Turning off the red dot, I flipped up the Diamondhead sights and ran a few drills with just the iron sights. The Diamondhead VRS-T handguard is slim, and its design offered a secure grip without any sharp edges.

Pistol-caliber carbines offer ammo compatibility with a sidearm. The Stag Arms Model 9T is an excellent partner for your 9mm pistol, offering reliability, control familiarity and less chance of overpenetration.

For more information, visit or call 860-229-9994.


  • CALIBER: 9mm
  • BARREL: 16 inches
  • OA LENGTH: 32.25-35.75 inches
  • WEIGHT: 7.9 pounds (empty)
  • STOCK: Collapsible
  • SIGHTS: Diamondhead flip-up
  • ACTION: Blowback, semi-auto
  • FINISH: Matte black
  • CAPACITY: 32+1
  • MSRP: $1,275

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