Hornady Manufacturing has shaken up the world of rifle cartridges once again with the release of the 338 ARC (Advanced Rifle Cartridge). This new cartridge is designed to excel in both subsonic and supersonic performance, positioning itself as a direct competitor to the well-established 300 Blackout. During a recent episode of the Hornady podcast, host Seth Swerczek was joined by Hornady Assistant Director of Engineering, Joe Thielen and Senior Ballistician, Jayden Quinlan. They dove deep into the technical advancements that the 338 ARC brings, and it’s clear that this cartridge means business.
A Subsonic Powerhouse

One of the key selling points of the 338 ARC is its incredible performance in subsonic configurations. According to the Hornady team, this cartridge was engineered to deliver superior terminal performance compared to the 300 Blackout. The 338 ARC, with its 307-grain Sub-X bullet, generates one and a half times more energy on target than the 300 Blackout. As Seth Swerczek pointed out, this significant increase in energy translates into a much larger wound channel, making the 338 ARC a more powerful option for hunters and tactical shooters alike.
Supersonic and Subsonic Performance Without Compromise

In many rifles, balancing subsonic and supersonic performance can be a challenge. Often, shooters need to adjust gas systems or swap out components to ensure reliable cycling between the two. However, Hornady’s engineers designed the 338 ARC to run flawlessly with both subsonic and supersonic loads in the same gas system. As explained in the podcast, this consistent pressure and gas generation mean shooters can enjoy seamless transitions without the usual headaches associated with cartridges like the 300 Blackout.
Designed with Versatility in Mind

The versatility of the 338 ARC extends beyond its ability to handle both subsonic and supersonic loads. The cartridge is also optimized for short-barreled rifles (SBRs) and AR-15 platforms, much like the 300 Blackout. However, where the 300 Blackout falls short, particularly in long-range subsonic performance, the 338 ARC shines. According to Jayden Quinlan, the 338 ARC can maintain subsonic accuracy and low standard deviations at distances up to 600 yards, far beyond the traditional range of the 300 Blackout.
A Cleaner, More Efficient Cartridge

One common issue with subsonic rounds, especially the 300 Blackout, is the amount of unburned powder left in the chamber after firing. This residue can lead to inconsistent cycling and requires frequent cleaning. In the video introducing the 338 ARC, Hornady’s team highlighted the cartridge’s clean-burning properties. Jayden Quinlan noted that the 338 ARC produces minimal unburned powder, even in subsonic configurations, thanks to its optimized case design and powder selection.
A New Standard for AR-15 Subsonic Loads

The Hornady team made it clear that the 338 ARC is not just another subsonic cartridge – it represents a leap forward in what shooters can expect from a compact, hard-hitting round. While the 300 Blackout has long been the go-to choice for those wanting a subsonic round in an AR-15, the 338 ARC promises to outperform it in nearly every metric. With greater energy, better terminal ballistics, and cleaner operation, this new cartridge sets a higher standard for subsonic shooting.
What About Supersonic Performance?

While much of the focus has been on the 338 ARC’s subsonic abilities, its supersonic performance is also impressive. Hornady is offering a 175-grain hollow point in their Black line of ammunition, designed to give shooters a flat trajectory and superior terminal performance. As Seth Swerczek discussed, the supersonic version of the 338 ARC outperforms the 300 Blackout in energy on target, making it a versatile round for both hunting and long-range target shooting.
Easy Gas System Tuning

One of the frustrations with the 300 Blackout is tuning the gas system to reliably cycle both subsonic and supersonic rounds, especially in AR-15 builds. Many shooters encounter problems where their rifles won’t properly cycle subsonic rounds, leading to malfunctions. However, as Hornady explained, the 338 ARC eliminates this issue with its balanced gas generation. Whether suppressed or unsuppressed, shooters can expect smooth cycling without needing to fine-tune their gas systems.
The Future of Subsonic Hunting

The 338 ARC wasn’t designed just for target shooters; it’s also an incredibly capable hunting cartridge. During the Hornady podcast, Quinlan compared the subsonic performance of the 338 ARC to a 44 Magnum, which has been a trusted round for hunters for decades. With penetration depths of 16 to 20 inches, the 338 ARC is more than capable of taking down game like deer, black bears, and hogs, even at subsonic speeds.
A Cartridge Built for the Modern Shooter

Hornady has been on the cutting edge of cartridge design for years, and the 338 ARC is no exception. Drawing on lessons learned from previous cartridges like the 6 ARC and 22 ARC, the 338 ARC is the result of years of research and development. As Seth Swerczek pointed out, this cartridge wasn’t just thrown together—it’s a well-thought-out solution for modern shooters who demand more from their ammunition.
The 300 Blackout’s Place in a Post-338 ARC World

The introduction of the 338 ARC raises an important question: where does this leave the 300 Blackout? While the 300 Blackout has enjoyed widespread use, especially in suppressed configurations, it seems the 338 ARC has surpassed it in almost every way. From cleaner operation to superior terminal ballistics and ease of use, the 338 ARC appears to be the new king of subsonic cartridges for the AR-15 platform.
The Verdict

The release of the 338 ARC marks a significant development in the world of subsonic and supersonic ammunition. As Hornady’s team emphasized, this cartridge was designed to offer a superior shooting experience with fewer compromises. Whether you’re a hunter looking for better terminal performance or a shooter looking for a cartridge that excels in both subsonic and supersonic configurations, the 338 ARC is a game-changer. As Hornady continues to push the boundaries of what’s possible, the 300 Blackout might just have to step aside.
The Future is Bright for the 338 ARC

As Hornady prepares to roll out this new cartridge in 2025, the excitement among the shooting community is palpable. With its impressive energy, clean operation, and versatile performance, the 338 ARC is poised to become a favorite among shooters and hunters alike. And while the 300 Blackout has had its moment in the spotlight, it looks like the 338 ARC is ready to take over as the go-to cartridge for those who demand the best.

Growing up in the Pacific Northwest, John developed a love for the great outdoors early on. With years of experience as a wilderness guide, he’s navigated rugged terrains and unpredictable weather patterns. John is also an avid hunter and fisherman who believes in sustainable living. His focus on practical survival skills, from building shelters to purifying water, reflects his passion for preparedness. When he’s not out in the wild, you can find him sharing his knowledge through writing, hoping to inspire others to embrace self-reliance.