Brownells 75th Anniversary - A Shooting Heritage

Precision Rifle Preferential Treatment

Precision Rifle Preferential Treatment

Crème de la Crème Gas Gun Build

By Richard Mann Photos by Sabastian Mann

Precision Rifle Build

Precision Long Range Gas Gun Competition used to seem like a contradictory association of words. The reason being that bolt guns have long been viewed as superior to semi-auto rifles when it comes to accuracy. While that holds some water, gas guns have come a long way and have carved out solid ground in the precision competition arena. Matches exclusive to semi-auto rifles can be found all across the U.S. and include divisions where competitors run either a .223 or a .308 in a "Tactical" division, or any other caliber in the "Open" division.

Some aspects of mainstream competitive shooting are akin to NASCAR, with a prevalence of bold logos, flashy jerseys, and being memorable just because those characteristics help push and sell products. A rifle build that not only keeps up with the Joneses of competition, but blows them out of the water, can't be anything near factory and damn straight better have that "wow" factor that hits you as soon as you lay eyes on it.

For this build, I needed a semi-auto rifle that could perform to the sub-MOA standards of precision rifle shooting and also look badass enough for spectators to drool. So with ABC (Always Be Cool) as the starting point, I hit up Brownells for insight as to what their best products would be for the build. From there, I culled the list down to components that not only delivered accuracy and precision, but looked cool, too. Because multiple variables influence precision rifle performance, I chose the crème de la crème of components.

While this rig was built with competition in mind, the chosen caliber makes it versatile enough for hunting. Having selected top-quality components for this project, it was balls to the wall, and I built a tack driver that consistently made hits out to 800 yards.

The Build

The make-or-break part of a target AR is the barrel. Investing in a well-made barrel will result in a more accurate gun. Because the barrel is so important, it was my beginning point. PROOF Research is known for making some of the most accurate barrels in the world. I went with PROOF's new Caliber Matched Gas System (CAMGAS) 24-inch carbon-fiber-wrapped barrel, chambered in 6.5 Creedmoor. Rather than copy-pasting a barrel design, PROOF moved the gas port 2 inches farther toward the muzzle than a traditional rifle-length AR gas system. The result is decreased recoil, making it easier to get back on target quickly. With this unique gas system, PROOF thoughtfully ships the barrel with a custom-length gas tube.

The decision to go with 6.5 CM was based on the desire to be competitive in the Open Division by capitalizing on the benefits of the caliber. Many competitors in Open run calibers from the 6mm family that have lower recoil, allowing them to get back on target more quickly and visualize impacts. The downside to those calibers is shorter barrel life due to higher velocities and the fact that most competitors have to reload their own ammo in order to get the perfect load for their gun. With 6.5 CM, I didn't sacrifice much in the way of felt recoil, and the barrel should last almost twice as long as a 6mm tube. And, since time is money, I didn't see an advantage in sitting in front of the reloading bench for hours on end prepping for matches. Instead, I can feed this rifle factory ammo and still get primo performance.

Next up on the list was the trigger. Earlier this year, Timney Triggers introduced the Calvin Elite AR Trigger, which is as customizable as any trigger ever produced. It comes with multiple trigger shoes, breaks at 1.5 pounds, and is very crisp. With this build, I canted and angled the trigger pad to sit exactly at the point where my finger naturally settles. The need for a good trigger is imperative; having the wrong trigger for the job could lead to a multitude of problems that result in more misses. This trigger is light and breaks like glass. When there is a lot of wobble, thanks to non-standard shooting positions, the Calvin Elite makes snatching the trigger while on target for that split second easy. One lesson I learned during this build: remember to tighten down the setscrews on the trigger housing. Miss that step, and the trigger pins will fall out. Oops.

The quality of JP Enterprises products is unsurpassed. So it was a no-brainer to go with a JP Low Mass Bolt Carrier Group and a JP Silent Captured Spring System. This rifle cycles especially smoothly and quietly when compared to those with standard buffer spring systems. Farther down the barrel, a Superlative Arms adjustable gas block lets me fine tune the gas flow. Moving on to the muzzle, the JP Tactical Compensator mitigates the recoil of the rifle.

The external features of this rifle match the superb quality of the internals. The Magpul PRS Gen 3 stock is, no surprise, fully customizable. One major aspect often overlooked by shooters is the need for an adjustable cheek piece to help you position your head in the right spot for consistent eye relief. Without it, it's too easy to get lost behind the scope and waste valuable time squirming around on your rifle trying to make a bad position shootable. The Magpul MIAD Gen 1.1 Grip provides a few options for better fit to your hand. Grip and stock went together like peas and carrots.

The Brigand Arms Edge handguard held up to testing when shooting in non-prone positions and while applying pressure to it. The strength of the handguard is impressive. It looks like it should flex, but it doesn't. One thing to keep in mind is that Brigand offers Picatinny and M-LOK options for more versatility during matches. This would allow for the bipod to be moved closer to the receiver than it is in the photo above, if need be.

Speaking of bipods, I went with a Harris. It's a tried-and-true piece of gear that'll take abuse and keep on giving. American Defense Manufacturing developed a mount for the Harris to attach to a Picatinny rail. It's stable and makes taking the bipod on and off easy. The KMW Lock Nut POD-LOC for the bipod allows for fast loosening and tightening of the Harris tilt feature.

Anyone who knows a thing or two about long-range shooting understands the importance of a good scope. If you want to hit targets far away, don't skimp on the scope. I mounted a SIG Sauer Tango6 5-30x56mm FFP scope. By far, its coolest feature is the LevelPlex that tells the shooter when the rifle is canted. A canted rifle can be one of the many reasons for misses. While looking through the scope with LevelPlex on, the indicators will tell you if you need to adjust cant left or right. If the indicators aren't visible, then your gun is level. The glass is crystal clear, and the scope tracks well whether you're dialing or using holdovers. This scope was the icing on my precision rifle cake. It comes with so many bells and whistles — it's a force to be reckoned with.

I wanted a girl with a bangin' body, so Brownells hooked us up with a Mega Arms match billet receiver set. The tension screw in the lower receiver gets rid of any slop between the upper and lower. But since this is a matched set, I didn't even have to adjust the tension screw. This receiver set is also fully ambidextrous. The included ambi bolt release is a nice touch that'll end up spoiling those who aren't used to ambi options. I upgraded the lower with a Seekins oversized magazine release and a Seekins Bolt Catch with a larger thumb pad, making the catch faster to find and use. For the lefties, I went full ambi by installing the Norgon Magazine release on the left side. And for the final touches on my ambi-baby, I installed a Battle Arms Development Ambi Safety. After taking a shot, bringing your trigger finger back and up puts the rifle back on safe in one sweeping motion, more efficient than flicking your thumb back to reach the same end goal. Also added for better control and ease of use: the Radian Weapons Raptor charging handle.

Shooting Prone

The Performance

Results on Target

Having well-made ammunition can make or break your performance. Many competitors load their own ammo so they can take ownership over its performance. But there are many great options on the market for factory-loaded ammo. I went with Hornady 6.5 Creedmoor 147-grain ELD Match. Using a Magneto Speed chronograph, the muzzle velocity average of a five-shot group was 2,648 fps, with a standard deviation of 14.

With a G7 ballistic coefficient of 0.351, shooting at 800 yards, and 10 mph winds, the wind hold is just over 1 mil. Not too shabby. I made consistent hits shooting from three positions commonly used in PRS — prone, kneeling/supported, and from a tripod — at distances between 300 and 800 yards on targets that were 2 to 4 MOA in size. For those who want to know how it grouped, I had to limit the amount of ammo used for accuracy testing and decided to test three five-round groups at both 100 yards and 300 yards. Each group shot was sub-MOA at both distances.

The Caveats

Building an AR on a .308 platform is not as plug-n-play as building an AR-15. There are a few different variants and a lack of standardization across the industry, save for the ubiquitous Magpul PMAG®. This can create compatibility problems when selecting components like a free-float rail. When you buy your receiver, you have to choose between the Armalite AR-10 pattern or the more popular DPMS LR-308. There are more products on the market that fit the DPMS pattern.

This rifle is "three-gun meets long-range precision." It features the best of both worlds, lightweight relative to its caliber, but also capable of dominating at distance. This setup will shine in Designated Marksman matches, Precision Rifle Series Gas Gun matches, 3-Gun Nation Precision matches, and for hunting where the weight of the gun won't limit your success.

Final Thoughts

This rifle is a unicorn. I dare you to find this same exact build already being used on a range. During testing, this beaut caught many eyes and garnered questions. The takeaway from those conversations

was that many people were surprised by the potential of a gas gun. Builds like this will change the way people think of and use the AR platform. I look forward to running the rifle through the ringer during a long-range match.

Rifle Viewed From The Backside

Make / Model / Product ID#


Mega Arms
Maten Ambi Receiver Set


PMAG® 25 LR/SR GEN M3TM Window


KMW Long Range Solutions
Lock Nut Pod-Loc


JP Enterprises
AR-308 Low-Mass Bolt/Carrier Group




JP Enterprises
AR-308 Silent Captured Spring System Gen2


Radian Weapons
AR-308 Raptor Charging Handle


$85 Magpul


$19 Magpul
AR-15 MIAD Gen 1.1 Pistol Grip


Battle Arms Development
AR-15 Lightweight Ambidextrous Safety Selector


AR-15/308 PRS Gen3 Rifle Stock


$242 High Standard
AR-15 Rifle Buffer Tube


AR-15/M16 Ambi-Catch Magazine Release


$90 Proof Research
PR-10 6.5 Creedmoor 24" Carbon Fiber Barrel w/Gas Tube


Yankee Hill Machine
AR-308 5/8" Crush Washer


Seekins Precision
AR-15/M16 Billet Magazine Release Button


Superlative Arms
AR-15 Adjustable/Clamp-On Gas Block (.875")


Advanced Armament
AR-308 Shim Kit for 5/8-24"


Seekins Precision
AR-15/M16 Enhanced Bolt Catch


JP Enterprises
.308 Tactical Compensator (5/8"-24 threads)


Muzzle Shim Kit


Timney Calvin Elite Trigger


American Defense Manufacturing
Picatinny Harris-Type Bipod Mount


SIG Sauer
Tango6 5-30x56mm First Focal Plane Rifle Scope


Brigand Arms
Edge 15" Carbon Fiber Handguard


S-BRM Bipod Sling Swivel Mount



Match Ammo 6.5mm Creedmoor 147gr ELD Match