The Best .338 ARC Magazine
Introduction
In this quick tip from Brownells, Caleb dives into a common question surrounding the 338 ARC caliber—what magazine should you use?
If you're not yet familiar with 338 ARC, it’s a 338 caliber round designed to run subsonic in an AR-15 platform. Think of it as the bigger, harder-hitting brother to the 300 Blackout. It's optimized for energy and mass while remaining subsonic, making it ideal for specialized applications.
338 ARC vs. 300 Blackout
When comparing the two, the 338 ARC clearly stands out in size and impact. With a noticeably heavier projectile, it packs more punch than the 300 Blackout, especially in subsonic setups. Caleb demonstrates this by showing off a hefty round pulled from one of his own builds—a tack driver that performed impressively at the range.
Range Performance and Build Video Mention
The rifle shown in the video has been thoroughly tested, and Brownells has a complete build video available for those interested in replicating the setup. Be sure to check it out for all the specs and parts used.
Magazine Compatibility Issues
At the time of filming, there aren’t any magazines specifically made for the 338 ARC. That creates a challenge for shooters, as many experience inconsistent feeding with various magazine options. This is a common hurdle with new calibers.
Why the Duramag 400 Legend Works
Caleb shares his solution: the Duramag 400 Legend magazine. While it’s made for the 400 Legend cartridge, it feeds 338 ARC flawlessly. In fact, it performs so well that even if dedicated 338 ARC mags are released, Caleb says he’ll stick with this one.
These magazines are available in multiple capacities and can be ordered directly from Brownells.
Feeding Issue Troubleshooting
If you’re experiencing issues like failed feeds or cycling problems with your 338 ARC rifle, chances are it’s not the gun—it’s the magazine. Switching to the Duramag 400 Legend could solve the problem instantly.
Final Thoughts and Support
If you’ve already tried this solution or have a different opinion, Brownells welcomes your feedback in the comments section. And as always, if you need help with anything firearm-related, give the Brownells tech line a call.
