Competition AR-15 Build – Featherweight Beast

Part of the excitement of being a gun writer is talking about firearms with my local gun shop, 29 Outdoor Gear. I get a kick listening to which firearms excite them and often learn something new. One day, while I was about to head out with a new bolt-­action rifle, owner Jerry Kunzman handed me a tricked out, skeletonized AR-­15 that he built with off-­the-­shelf parts.

It was so light, I thought it was fake. It weighs 3 pounds, 13 ounces. What’s more impressive to me is that this featherweight is no safe queen; it’s his competition AR that gets subjected to heavy use.

I recently spent a day shooting it with him and was blown away by its performance. It was light, but it shot like a fine-­tuned beast, so I dubbed this AR-­15 chambered for 5.56 NATO/.223 Rem. the “featherweight beast.”

The Experiment

Like many other lightweight AR projects, the inspiration for this AR was an experiment in weight reduction, but it needed to also compete and win against heavier rifles. For the build, Kunzman avoided polymer and plastic in favor of carbon fiber, aluminum and titanium to drop weight but keep strength. Since this is a competition gun, the ergonomics had to be perfect.

The build started with the receivers that were machined from 7075 T6 aluminum. The upper was made by F1 Firearms and was skeletonized by the manufacturer. While the lower receiver came from Ghost Firearms and featured a skeletonized magwell, Kunzman milled out more weight where he could.

As I looked through the maze of holes in the receivers, Kunzman assured me, “I don’t baby this, but at the same time, it’s not a combat AR.”

With so many holes in the AR’s structure, I believed a drop in the mud would stifle its operation. However, a testament to its dependability was that a week before I shot the featherweight beast, its owner took it through a week of hard training. During that time, he experienced only two malfunctions, both related to a bad magazine.

Performance Trumps Weight

Some builders seeking the ultimate in lightness will cut weight by chopping the length of the stock. The negative effect to this is a cramped shooting compartment. Since performance trumps weight, Kunzman used a full-­length carbon-­fiber stock from Smoke Composites that weighs only 4.1 ounces.

“I wanted to keep a length of pull that works well for me in competition,” Kunzman said. “This fixed stock is as minimalist as one can get. It’s a buffer tube with a carbon-­fiber buttplate and a 7075 aluminum threaded collar.”

---

Maintaining full-­length ergonomics also applied to the handguard. Kunzman shoots with his support arm fully extended and chose the 15-­inch Brigand Arms EDGE Handguard. The handguard is a patented carbon-­fiber braid with an aluminum barrel nut and steel jam nut. It’s free floating and weighs a scant 4.3 ounces. Aesthetically, the handguard is in between beautiful and plain depending on the angle. It looks fragile, but it’s not.

To reduce weight with the bolt carrier group (BCG), Kunzman chose a JP Enterprises Ultra LMOS bolt carrier made of 7075 T6 aluminum with a titanium firing pin. It has a very lubricious coating that feels as slick as water on glass. The bolt is a standard steel version.

The benefit of a low-mass carrier is that it will cycle faster given the same force, but the downside is that it will wear quicker than a steel bolt carrier. A lighter bolt carrier makes a midlength gas system with an adjustable gas block a must to fine tune its cycling. JP Enterprises cautions against using a carbine-­length gas system. A lighter carrier also means reduced felt recoil which gets you back on target quicker.

Trigger Time

The trigger is not a lightweight part, but it’s one of the strangest triggers I’ve shot. Made by JP Enterprises, the Armageddon Gear Revolution Trigger’s shoe is a rolling pin and breaks at 3 pounds, 2 ounces. This was my first introduction to the trigger, and I’m glad I didn’t read anything about it because its description reads like hyperbole. As it is, I was able to experience its mechanics without any preconceived notions.

Every trigger I’ve put my finger on, whether straight or curved, has a flat shoe surface which cradles the meaty pad of the index finger. The initial pull of the trigger consists of squishing the pad against the shoe’s broad surface until the index finger’s bone compresses the pad and pulls the trigger rearward.

With the JP Enterprises trigger, there’s very little surface area to cradle the finger’s pad, concentrating most of the pressure on a small point. The difference is similar to sitting on a bench or sitting on a thin branch, your butt bone will feel the pressure on the branch. To my surprise, this gave my finger more control of the trigger. Add to this, the shoe spins freely on its vertical axis.

Common sense will tell you that your finger will roll off easily, but in practice, the spinning works to set your finger in a neutral position as it moves the trigger rearward. The dynamics of this was noticeable when shooting slow steady shots as well as rapid fire.

The muzzlebrake is a titanium V7 Furion with a few modifications. Kunzman drilled an additional hole at the base which bisects the threaded muzzle to fine-­tune the blast’s direction and keep it as flat of rise as possible. Considering that the Faxon 16-­inch barrel is pencil thin and weighs 18 ounces and the handguard weighs just 5.12 ounces, you would expect some muzzle rise, but it was close to flat for me.

The part that received the most chopping was the aluminum buffer. Typically, a standard buffer is 2.5 inches long. Kunzman chopped this down to a nub of just half an inch. To his surprise, while tuning the bolt’s cycling with Wolf Gold .223 Rem. 55-­grain ammo, he found the bolt cycled fine with a stub of a buffer. So good was its operation, Kunzman filed a patent request on the design.

For weight-­weenies, the sub-­4-­pound weight is a reason to run a victory lap around the track, but if the AR cycles poorly, recoils harshly, has excessive muzzle rise, or is an inconsistent shooter, it might as well be a door stop.

Lightweight Performance

Anxious to see and feel how this featherweight performed, I shot several failure drills at an IPSC target. A failure drill is two shots to the chest followed by one to the head. I was amazed at how easy it was to transition from the body to the head and precisely stop the rifle once the red dot landed in the head’s “A” zone.

I ran the drill several times going faster and faster and always felt in control and aware of each round. Interestingly, I was very aware of the pressure of my finger on the trigger. It wasn’t a distraction. I just felt weird having full control of the trigger.

I next turned my attention to a row of 10 steel plates sitting on the hillside 40 yards away. I’m so used to having some barrel rise that I initially hopped the barrel from plate to plate. I soon realized I didn’t need to do this. I could just swing the barrel from plate to plate. The way Kunzman modified the muzzlebrake, muzzle rise was tamed to a small blip.

One of the many things that shocked me was how smooth and effortless this AR ran. Part of that can be attributed to the carbon-­fiber stock and handguard. There is a significant difference between how aluminum and carbon fiber transmit forces. I know this from cycling where I’ve replaced aluminum forks with carbon-­fiber forks. The aluminum transmitted all the bumps while the carbon fiber deadened them for a much smoother ride.

When shooting the featherweight beast, the forces generated by shooting are pacified by the handguard and stock. The only force that stands out is the clank of the BCG reaching the apex of its rearward movement and slamming forward.

For the accuracy test, I made it difficult on myself by using the 1X red dot instead of a magnified optic. I shot three three-­shot groups at 100 yards using an Aimpoint Micro T-­1 with a 2-­MOA dot. At that distance, the 2-­MOA red dot covered most of the 3-­inch target leaving for a tiny black halo. My best three-­shot group shot was .25 inch. Incredible.

Overall, the performance of the AR defied my expectations. I expected aggressive recoil, greater muzzle rise and acceptable accuracy. Instead, it challenged my notions about the role weight plays in accuracy. It also showed me how a rolling-pin trigger is a great idea, and a properly tuned AR is effortless to shoot.

The featherweight beast is a one-­off build, but Kunzman can build a similar one for around $2,800. A big price to pay to shave all that weight, but its performance will have you walking the highway collecting empty cans and bottles to amass enough change to buy one.

To read more articles like this, click here to purchase a print or digital copy of Guns & Ammo AR-15.