338 ARC Bolt Action AR: It Gets Worse The Longer You Look At It [BUILD]

Inspiration can find you when you’re least expecting it. Flipping through your favorite magazine, visiting a museum dedicated to the masters, or warming your bones in a hot shower. Where and how you find inspiration often dictates the quality of what it inspires. 

Michelangelo was inspired by ancient Greek and Roman art and, with his chisel, carved The David, Madonna of Bruges, and many more. 

I was inspired by Reddit and used a Dremel to chop my bolt carrier group in half. The similarities are uncanny.

THE BUILD

338 ARC is a newer cartridge from Hornady built to replace 300 Blackout and 8.6 Blackout. Throwing 307-grain bullets at 1,050 FPS from a 12.5-inch barrel, 338 ARC packs a punch and does it quietly with a decent suppressor. My semi-auto thumper is a wonderful gun I’ve been using to test and enjoy 338 ARC. But you know what can help make a gun even quieter? 

Making it bolt-action instead of semi-auto.

Bear Creek Arsenal recently released a line of bolt-action uppers for AR-15s. A clever little design, these use standard AR handguards and standard AR barrels, combined with a proprietary BCG and upper receiver. Sold as complete rifles, complete uppers or just the stripped receiver and BCG, 

For this project, I went with just the stripped receiver and BCG since I had a handguard and BCG I wanted to add myself.

The barrel is a 12.5-inch 338 ARC provided by Ballistic Advantage, the handguard is an old carbon-fiber Lancer I’ve had sitting on my parts shelf for years. 

Muzzle device and suppressor were pulled off my semi-auto 338 ARC build, both from TiON. I’m a big fan of this Dragoon 8.6 suppressor and its performance with 338 ARC.

The folding brace is the dual-folder from Strike Industries. 

DREMEL GOES BUZZZZZ

For legal reasons, you should know: I’m not an engineer or a gunsmith, and BCA does not approve this. You should not take my advice on what you can or can’t safely cut off your gun. You should always follow recommended safety precautions and never do what I did. Ever. This is not a “how to” article; this is simply documenting what I did because I have bad ideas. 

The BCA bolt-action bolt carrier is about the same size as a normal AR BCG. But since this is a bolt-action upper, most of the working bits are located in the front. So… I chopped off the ass-end of the carrier. At full length, the BCG requires a buffer tube to cycle just so that material has somewhere to go. Without that rear part of the BCG, I don’t need a buffer tube and can fit a folding brace on it instead.

This major and probably unsafe modification complete, it was time for the range.

ON THE RANGE

This build is lightweight at barely over 6 and a half pounds, including the suppressor. It is so much fun to hold and pass around to your friends. It’s handy, it’s light and it looks like a 3-legged dog with floppy ears.

It also shoots like a 3-legged dog trying to race. It really just doesn’t work very well. 

The list of problems with this abomination is pretty long, so let’s hit the highlights. 

• Bullets only successfully feed from the left side of the magazine
• Bolt must have lateral pressure as you cycle it in order to cycle at all
• 40+ rounds fired, zero brass ejected correctly
• Single feeding is actually more successful than loading from the magazine

Cycling and ejecting are the fault of the BCA upper. The way the bolt and BCG are designed requires pushing the bolt toward the receiver while running the bolt to prevent binding. While pressure-bearing lock up is handled by the bolt rotating into the barrel extension, the bolt handle still hooks onto the ejection port. Because of that, the ejection port is small for the fairly large 338 ARC brass to eject. So far, none have cleared it.

Turning the gun sideways and shaking it helps ejection, but that’s not ideal.

I thought feeding was the fault of the Ballistic Advantage barrel. I even went so far as to pull the barrel and check the feed lips. Finding a burr, I assumed that was the problem. It wasn’t. Even if I switch barrels to my Faxon Firearms 338 ARC barrel, which I know works, this upper still won’t feed from the right side of the magazine.

All 8 magazines I have exhibit the same problem, they tilt down slightly and cause the right-hand cartridge to nose dive into the feed lips. But those same magazines work fine in my other 338 ARC upper.

If I push the magazine forward, it tilts the bullet high enough to feed correctly.

Changing the lower hasn’t helped, so that isn’t the cause. Maybe the upper has a tolerance issue? Maybe it’s a stacking issue of all these parts combined? I honestly don’t know. The one magazine that feeds most of the time is an Amend2 6 ARC magazine, which is made even weirder because that magazine is my least reliable magazine when shooting 6 ARC.

When the gun does fire, it’s very satisfying. 338 ARC is a great cartridge, and the TiON Dragoon 8.6 with a bolt action makes the system Hollywood quiet.

Supersonic rounds feed perfectly because of the sharper nose of the bullet, and I would expect subsonic rounds that don’t feature Hornady’s SUB-X bullet would also feed fine, but I don’t have any of that ammo to test my theory.

LOOSE ROUNDS

338 ARC is an interesting and, so far, impressive new cartridge, and it’s fun to experiment with new builds. Some of them won’t always work out perfectly, but it’s an experience at least. Ultimately, I’m left disappointed by this Frankenbuild. While the idea is good, it fell short of what I hoped.

Different ammo would probably solve the feeding issue, but the cycling and ejection problems are inherent to the BCA design. Still, for a super quiet pop gun packing a punch — this fits the bill. Just don’t expect to send more than one shot per 10 seconds.