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Win This Rifle Build! 9mm Pistol Caliber Carbine

Primary Arms Staff

7/6/2020 1:22 pmwww.primaryarms.com

This Giveaway has ended. Congratulations to our winner, James F. in North Dakota! You can view all current and past giveaways on our giveaway blog page.

Another month, and another awesome rifle giveaway is in the works. This time around, we decided to go in the opposite direction from last month’s purpose-built long-range precision rifle. With the summer weather rolling in, this build had to be just as fun to shoot in both indoor and outdoor ranges. That’s why we built a 9mm AR-15 pistol caliber carbine, so read on to learn about which parts we used and why. If you need ideas for your own pistol caliber carbine (PCC) build or are feeling particularly lucky and want to learn how to win it for free, be sure to read to the end (Or just scroll down, it won’t hurt my feelings). However, first I want to talk about why anyone would even want an AR-15 chambered in a caliber designed for handguns.




AR style carbines chambered in pistol calibers have been rising in popularity over the last few years for a variety of reasons. Whether it be personal protection, competition use, or even just fun at the range, these versatile carbines offer a surprising amount of utility. It doesn’t hurt that the ammunition is affordable as well, so you can pile it high and have plenty for multiple range sessions. Additionally, 9mm carbines have low recoil and are extremely easy for new shooters to practice with, making it fun for everybody. When combined with a stock and red dot sight, these carbines can be extremely fast and accurate while making short work of the target at your local steel challenge matches. Even 3-Gun has a class specifically for people running a PCC. Additionally, because 9mm is already such a popular cartridge, there is a multitude of ammo available for plinking, self-defense, and even suppressed use. It also makes range trips much more manageable when you can take ammo that will function in your handgun as well as your rifle. This is just a brief overview of why pistol caliber carbines have become popular and there are many more reasons that we could dedicate an entire article to. If this has piqued your interest, then let’s continue to the parts list, so we can explain why we chose the parts we did and why you might want to win it or build your own.


Click on the table below to see a complete listing of all our build's parts on primaryarms.com.



Dedicated 9mm AR-15 Receiver Set

There are many ways in which you can put together a 9mm AR-15 PCC. If you already have a standard AR-15 lower receiver laying around, then you already have the foundation for your build. There are a variety of companies like Stern Defense that have designed magazine well conversions that fit snugly into Mil-Spec receivers and allow the use of 9mm Glock mags, M&P mags, and even Beretta magazines. These magazine conversions are great because it doesn’t require any permanent modification, so you can swap your 5.56 upper back on, change out your buffer weight, and get back to shooting a rifle cartridge. It’s like having two guns in one. The other option is to build it from the ground up with a dedicated 9mm lower receiver.




For this build we’re using the Cross Machine Tool UHP9 Lower Receiver. This receiver is machined from a single billet of 7075-T6 aluminum giving CMT complete control of the external dimensions. This allows them to design a magazine well that is compatible with 33-round Glock 17 magazines, as well as a streamlined design with a clean profile. This lower also comes with a ton of quality of life improvements like an upper tensioning screw, integral magazine release button, and threaded roll pins that are much easier to install than the standard hammer and punch type (you’re welcome, Jimmy). The most important reason is that it looks freaking sweet when paired with the CMT UPUR2 Slick Side upper receiver. It is made from the same materials and the same processes, allowing them to remove unnecessary weight like the forward assist assembly and making all the lines match with the lower. The integral tensioning screw prevents the two receivers from wobbling, making for a very premium feel. Another benefit of this receiver set is the compatibility with Standard AR-15 components, so we have a huge variety to choose from.




The Trigger and Lower Parts

While the lower receiver features .154” pin diameters and is compatible with standard AR-15 triggers, it is a good idea to get a trigger that is designed with 9mm bolts in mind. The CMC Single Stage 9mm PCC trigger features a hammer that has been modified to reduce unnecessary wear and potential reliability issues. This trigger is made from the same materials as their other triggers like the 8620 alloy steel drop in housing and S7 tool steel internals. The 3.5lb trigger pull is crisp and smooth with a fast reset that makes this a great option for competition use. To finish out the lower receiver, we chose to go with the Foxtrot Mike Products Premium LPK because the parts are reliable, the kit comes with an ambidextrous safety selector, and it doesn’t include a pistol grip. That way we can use the B5 Systems Type 23 P-Grip for enhanced ergonomics. The near-vertical angle makes for a much more comfortable grip while also ensuring proper indexing with the trigger.




Another way we improved ergonomics is with the Magpul MOE Slim Line Carbine Stock. This stock is extremely compact and lightweight making it perfect for a carbine build. It is incredibly durable and offers a tight fit on Mil-Spec buffer tubes to prevent rattle and features integral QD sling swivel slots. For the buffer assembly we chose the Luth-AR collapsible 6 position buffer tube to give you plenty of adjustment. It also comes with a 9mm tuned buffer weight and stainless-steel recoil spring. Because the 9mm PCC uses a blowback action instead of being gas operated, the weight of the buffer—as well as the bolt—is extremely important in ensuring a reliable firearm. This 9mm tuned buffer system will go a long way in keeping this carbine running smoothly.




The 9mm Bolt, Barrel, and Upper Parts

Speaking of running smoothly, we chose to go with the 9mm Bolt from Foxtrot Mike Products which features a salt bath Nitride finish. This type of surface finish is made by diffusing Nitrogen and Carbon into the material to physically change the surface characteristics, making it more wear resistant, durable, and slick. Technically it is not called a bolt carrier group because the entire hunk of 8620 Carpenter steel is the bolt unlike a traditional AR-15 BCG with a rotating bolt and locking lugs attached to a carrier. The blowback system does not rely on the rotating bolt and gas system to delay the action from opening. Instead it relies on the mass of the bolt and buffer setup to keep it closed long enough for the bullet to leave the barrel and pressures to drop to safe levels before the bolt cycles. One area where we did save weight is the barrel.




For the barrel we decided to go with the Foxtrot Mike Products Ultralight 16” because it features a pencil profile and is made from 4150 Chrome Moly Vanadium steel. This type of steel is great for a barrel because of its long-lasting durability and heat resistance. It also features the same type of salt bath Nitride finish as the bolt and even has feed ramps to reliably chamber different types of rounds. And when those rounds are sent down range, you can be sure the button rifled 1:10 twist rate will get them there accurately and consistently. To keep you on target, we included the LANTAC Dragon 9mm Muzzle Brake with a highly effective three chamber design that reduces muzzle climb with minimal side blast. Protecting your hands from the heat of the barrel is the Bravo Company MFG M-LOK Compatible Modular Rail System that free floats the barrel and has plenty of mounting options for grips and accessories. For charging the carbine, we included the Seekins Precision DNA Charging Handle with a large, skeletonized latch that is easy to manipulate.




The Sighting System

No PCC is complete without a Red Dot Sight mounted on top, so we are throwing on our Primary Arms Silver Series SLx Advanced Rotary Knob Micro Dot in an American Defense Quick Detach Mount. This setup places the red dot at a lower 1/3rd co-witness with the Midwest Industries Combat Rifle Folding Sights. This sight set features a minimalist design with a large rear aperture and A2 front post optimal for quick target acquisition. Not that you will ever need to use them because the Primary Arms Silver Series Red Dot Sight features a 50,000 hour battery life and a lifetime warranty. The industry standard footprint allows us to use the American Defense AD-T1 quick detach mount that ensures it will stay locked down to the picatinny rail until you feel the need to remove it.




How to Win This Rifle!

So, there you have it. Another awesome rifle built from some of our favorite parts and it even comes in a 42” Plano Rifle Case. Unfortunately, I’m not allowed to enter this competition so I’m building this rifle out of my own pocket! Luckily for you, all you need to do is follow the instructions below and this 9mm AR Carbine could be yours.

You have multiple chances to win this rifle, and some refresh daily so pay attention! Visit our Giveaway landing page to learn more about the terms and conditions and follow the instructions to have your entries counted. The giveaway ends June 30th 2019, at 11:59pm CDT. Winner MUST be legally able to possess a firearm and pass a federal background check. Winner is responsible for all taxes. If the winner is unable to meet the requirements necessary to take ownership of the firearm, the winner will be granted the total value of the prize package, $1,738.25, in cash. Exclusions do apply, no purchase is necessary.