The PWS MK107 Piston AR Pistol


Primary Weapons Systems, Inc. (PWS) of Boise Idaho has been in the high-performance AR biz for long enough to have some serious street cred. They are best known for their top shelf MK1 and MK2 series rifles and uppers in addition to their Triad series of flash suppressing compensators. Well PWS has now taken to making an AR-style pistol.

And its piston driven.

Wait, what?

Yes campers, the PWS MK107, Mod 1 Pistol uses a long-stroke fixed operating rod design with an adjustable gas block. According to PWS, it is the “only piston-driven pistol on the market today that was designed from the ground up as a 7 platform, the PWS MK107 pistol is a dream come true for those looking for the shortest possible package and the reliability of a full-size rifle”

What do you mean short?

Well how about 24.5-inches overall with a 7.75-inch barrel?

Of course, piston-driven AR pistols are not completely new. Rock River Arms has a piston driven AR pistol and there is always the old-school OA93 out there. However to compare these guns to what PWS has going for it is like simply saying the Dodge Charger and the Bugatti Veyron Super Sport are both fast cars. The MK107 pistol brings a whole ‘nother level of performance to the picture.

PWS uses state of the art CNC Machines (google Okuma Multus B300 lathes and HAAS VF-4 mills for more info there) and doesn’t skimp on quality. Their separate components have a lifetime warranty, which should tell you all you need to know there. For the ingredients they don’t make in-house, they shoot for quality. This includes VLTOR KeyMod Systems, BCM-Gunfighter charging handles, and Magpul MOE grip/trigger guards, PMAGs, and MBUS sights.

Calling the Triad…

The pistol comes outfitted with one of their muzzle-rise killing 556 Triad flash hiders. With a trio of  open slots at 270, 150 and 30 degrees, these advanced three-pronged hiders have given us the effect of pushing the muzzle down and left in tests when replacing old A2 style hiders on our shop ARs. Its neat idea borrowed from the proven AK slant brake that doesn’t add a lot of extra weight to the gun and without the ‘ping’ often found in more classic three-pronger designs. It works as a suppressor compatible mount for the Gemtech Halo among others for those who like a little quiet time. Plus it just looks badass.

That’s a nice chamber throat you have there…

Instead of stock .223, this bad boy comes chambered in .223 Wylde. The Wydle round takes the best of what makes the .223 Rem and 5.56mm NATO and couples it to a large (up to 80-grain) bullet for extra performance. Rifles throat chambered for .223 Wylde will typically accept both .223 Remington and 5.56×45mm NATO fodder, and do it very accurately, but you still have that Wylde capability on tap.

Our thoughts

AR pistols are an acquired taste. Buy nature they are something of the ‘poor-man’s SBR’ as they combine an ultra-short barreled rifle platform without the downer of having to sink $200 into a tax stamp and jump through ever-changing BATFE NFA hoops. Of course, you sacrifice the ability to use a regular buttstock due to said NFA rules, but you wind up with a very capable five-pound pistol. It’s a series of trades, as is most things in life.

With increasing numbers of these AR handgun platforms coming on to the market, it’s nice to see one that doesn’t sacrifice quality for the sake of making a fast buck. Then again, it’s also hard to figure out if $2000 is worth it to have what amounts to for many shooters as not much more than a range toy.

However, these guns are growing in popularity. The option of having a briefcase or backpack sized ‘go-gun’ riding along with you in public for off-body carry is a growing subset of those who find these guns big medicine to meet the threat of an active shooter scenario with more than a spork in their hands.

In a moment like that, would you rather a $500 AR pistol with questionable internals and a funky pedigree, or a gun like the MK107?

Screen shot 2014-01-02 at 1.46.21 PM


CALIBER .223 Wylde

WEIGHT 5 lbs, 2 oz. (2.34 kg)

OVERALL LENGTH 24.5 (62.2 cm)

BARREL LENGTH 7.75 (19.7 cm)

MUZZLE VELOCITY 2368 ft. /sec (with M855 5.56mm NATO)

MUZZLE ENERGY 772 ft. /lbs

MSRP Price: $1,949.95

(But hey, if you can find a nicer piston AR pistol for less, buy it)

Hint, hold your breath.


Christopher Eger

2 thoughts on “The PWS MK107 Piston AR Pistol

  1. Pingback: The PWS MK107 Piston AR Pistol | laststandonzombieisland

  2. Pingback: if not dieting then what

Leave a Reply

Your email address will not be published. Required fields are marked *

You may use these HTML tags and attributes: <a href="" title=""> <abbr title=""> <acronym title=""> <b> <blockquote cite=""> <cite> <code> <del datetime=""> <em> <i> <q cite=""> <strike> <strong>