Is 50 Years Of AR-15 Development Overhyped?

Engineering vs Sales Hype On The the Primary Weapons Systems MK1

Article and photos by Robert Strickler


As the AR-15-style rifle becomes more and more popular, a few companies have emerged to improve upon this iconic firearm. One of the companies at the forefront is Primary Weapons Systems (PWS) in Boise, Idaho. PWS was started in January of 2008 and was initially based out of a 2,400 square foot, roll-up door building. Today, PWS has grown to be one of the largest manufacturers of piston-operated AR-15 platform rifles in the country. They employ 84 people who are all passionate about providing incredible rifles and excellent customer service.

During a recent visit to PWS, I was able to take a tour of their expansive facility. At one point, I asked Stacey of dealer development and sales what parts they actually produce themselves. He replied, “It would be easier to tell you the parts we don’t make here than those we do.” It is fantastic to see a company produce the majority of their components in-house, and as the PWS website states: “Any components that are not produced by PWS are purchased from only the best manufacturers to ensure the highest quality products are delivered to the end user.” One look at their rifles and this fact becomes immediately apparent.

Aiming an MK1 AR15

While at PWS, I was able to get my hands on a brand-new MK1 rifle. The MK1 comes in a variety of barrel lengths; my test rifle was the MK116 model featuring the 16 ½-inch barrel. The first thing that stood out to me was the well-balanced and lightweight feel of the rifle and its sleek design. This is partially accomplished by their 12-inch, free-floating key-mod hand guard produced in-house on one of their many CNC (computer numerical control) machines. Another nice touch that also shaves off weight is the Enhanced Buffer Tube that comes standard on all their rifles. Lastly, as mentioned above, the components on this rifle are top-notch, from the Magpul furniture and flip-up sights, to the Gunfighter charging handle. PWS rifles are one of the nicest “off-the-shelf” rifles I have seen.


A FEW DAYS LATER, I found myself out on the range so I could put the MK1 through its paces. Being a fresh, clean rifle, I was able to get a good feel for the benefits of the piston-operated system. The main benefit of the piston-operated system versus the standard direct impingement (DI) system is that it keeps the action of the rifle cooler and cleaner.

This is accomplished by keeping the majority of the gas and carbon out of the receiver. With a DI rifle, the gas travels all the way down the gas tube to meet the gas key on the carrier, but with a piston-operated rifle such as the MK1, the gas enters the gas port and actuates a piston causing the action to cycle. This results in significantly less hot gas and carbon entering the receiver itself.

OLYMPUS DIGITAL CAMERA“That’s neat, but how does that help me?” you say. Well, the piston operating system on the MK1 has several significant benefits in “real world” application. As competitive shooting accompanied by countless hours of practice, and weekend defensive training courses become more popular, people are firing a lot of rounds in a short amount of time. With a piston-operated rifle like the MK1, this means less time cleaning and more time shooting.

During my time spent at the range, I put 150 rounds through the MK1 without even the slightest hiccup. It performed flawlessly during slow and rapid fire. The MK1 points nicely, and the balance and feel I immediately noticed days earlier once again became apparent on the range.

While firing, I also took note of the quality ALG trigger PWS specs on their rifles; it had a crisp break with almost no creep.

Lastly, another key component of the rifle produced by PWS is their Flash Suppressing Compensator (FSC). Not only did this slick-looking muzzle device reduce felt recoil, it also did a good job at minimizing muzzle flash. When I finished firing the final magazine, I immediately pulled the takedown pin to inspect the inside of the receiver, the bolt and carrier. I can honestly say it was almost like I hadn’t fired it. Very little carbon had accumulated and the entire system was dramatically cooler than a standard DI rifle would have been. I was very impressed how well the piston system works on the PWS MK1.

In conclusion, the MK1 was an all around pleasure to shoot; I didn’t want to take it back to PWS when I was finished with this article. If you’re looking for a light, sleek, high-quality, piston-operated AR-15 platform rifle, whether it be for varmint hunting, 3-gun competition, or personal protection, the Primary Weapons Systems MK1 is an excellent choice. See the rest of their line up of MK1 and MK2 series.
Editor’s note: In addition to being a writer, Robert Strickler is also the owner and founder of Modern Musket, To learn more about PWS and their rifles visit their website