Why the 6mm ARC Should Be Your Next AR-15 Build

6mm ARC

You may have heard the buzz around 6mm ARC, but perhaps you’ve been burned in the past and you’re hesitant go go out and invest in the latest and greatest, with no promises of long term success. We don’t blame you one bit, but the bottom line is that shooters we talk to daily say it is the real deal. That said, with the rise of the 6mm ARC, many questions have arisen about what it takes to get started shooting this round and whether it is perhaps overhyped.

6mm ARC

What is the 6mm ARC?

So, just what is 6mm ARC? It is a medium-caliber cartridge that fits into the standard AR-15 platform. Designed with a high ballistic coefficient, the 6mm ARC has superior aerodynamic properties, resulting in better accuracy and stability over long distances.

The only difference between a 6mm ARC build and a .223 build is the barrel, the bolt (the same AR-15 carrier is used), and the magazines. .223 magazines cannot be used due to the case size. The 6mm Advanced Rifle Cartridge (ARC), developed by Hornady in 2020, is designed to bridge the gap between the traditional 5.56mm NATO and larger calibers like the 7.62mm NATO, offering enhanced performance without significantly increasing recoil.

This cartridge offers a combination of light recoil, flat trajectory, and impressive terminal performance, making it suitable for various shooting applications, from target shooting and competition to hunting medium-sized game. The 6mm ARC typically uses heavier bullets than the 5.56mm NATO, ranging from 103 to 108 grains, enhancing its long-range capabilities.

How is it Better?

Better is often subjective, this is a cartridge actually delivers where it counts. Several factors contribute to the 6mm ARC’s superiority over more traditional rounds like the 5.56mm NATO and even the .308 Winchester that we’ve all grown very familiar with over the years.:

  1. Ballistic Performance: It provides significantly better ballistic performance, especially at longer ranges. Its higher ballistic coefficient ensures less wind drift and drop, improving accuracy and consistency.
  2. Versatility: The cartridge is versatile for various applications. Whether for precision shooting, competition, or hunting, it excels due to its combination of power and accuracy.
  3. Reduced Recoil: Despite its enhanced performance, the 6mm ARC maintains manageable recoil, beneficial for follow-up shots and maintaining accuracy during rapid fire. It delivers substantially less recoil, allowing shooters to spot their own shots.
  4. Efficiency: It achieves its performance without requiring significant increases in powder charge or pressure, making it an efficient round that balances power and wear on the rifle. The AR-15 platform with the 6mm ARC also features a higher magazine capacity and offers a 30-35% lighter-weight package compared to the AR-10/.308 Win system.
6mm ARC

Why Should the 6mm ARC Be on Your Short List?

If you’re like us, you probably have more than a handful of 5.56 guns in your safe. So, then, just what are you supposed to do? Start a shotgun collection? We’d pass on that. Instead, if we may be bold, we’d suggest you build yourself a 6mm ARC. For enthusiasts who reload and already have a collection of ARs chambered in 5.56mm, the ARC offers a compelling reason to expand their repertoire. Here are a few reasons why the 6mm ARC should be considered for the next rifle build:’If we may be bold, we’d suggest you build yourself a 6mm ARC. For enthusiasts who reload and already have a collection of ARs chambered in 5.56mm, the ARC offers a compelling reason to expand their repertoire. Here are a few reasons why it should be considered for your next rifle build:

  1. Enhanced Reloading Experience: Reloaders will appreciate the 6mm ARC’s potential for customization. Its ability to handle a range of bullet weights and styles allows for tailored loads that maximize performance for specific purposes. It can run bullets from 55-grain up to 108-grain, based on a 6.5 Grendel case with the shoulder pushed back and necked down to 6mm. This provides good case capacity and muzzle velocity, suitable for anything from prairie dogs to long-range shooting.
  2. Improved Performance: For those looking to step up from the 5.56mm NATO, the ARC provides noticeable improvements in range and accuracy without needing a completely new platform. Existing AR-15 owners can upgrade their rifles with a new upper receiver and barrel, making the transition cost-effective. Hornady designed the round to be optimal in an 18” barrel, but civilian offerings show that 18”, 20”, and 22” barrels are popular choices.
  3. Fun and Innovative: Exploring the capabilities of the 6mm ARC can add a new dimension of fun to shooting. Whether experimenting with handloads or pushing the limits of long-range shooting, the 6mm ARC offers a fresh and exciting challenge. The cartridge delivers much of what larger cartridges can and everything smaller cartridges can’t, making the AR-15 even more versatile.
  4. Practical for Hunting: The 6mm ARC’s terminal ballistics make it suitable for hunting medium-sized game, such as deer and hogs. Its balance of power and precision ensures ethical and effective shots. It’s a deadly coyote round, blending the AR-15 and AR-10’s capabilities, and has been proven effective on whitetails and pigs.
6mm ARC

Performance Metrics

The numbers that 6mm ARC puts up tell the story. Factory ammunition with an 18” barrel reaches around 2,620-2,630 fps muzzle velocity. A 20” barrel jumps to approximately 2,670 fps, and a 22” barrel achieves around 2,690 fps. Reloaders can enhance these numbers, with an 18” barrel potentially reaching mid-2,700s fps without pushing pressures. Lighter bullets, like the 55-grain, can reach 3,200-3,300 fps comfortably out of a 20” barrel, while 87-90 grain bullets can reach around 2,900 fps in an 18” barrel, pushing to 3,000 fps in a 20” or 22” barrel.

The only issue encountered with the 6mm ARC is the availability of factory ammo, initially impacted by the COVID-19 pandemic. However, availability has improved, and Hornady’s support ensures a stable supply of ammunition. The 6mm ARC is expected to remain a prominent choice due to its versatility and performance.

6mm ARC


It seems like a “hot new round” for the AR comes out every year, only to eventually fall by the wayside. That does not seem to be the case with 6mm ARC. Yes, in 2024, availability is still a challlenge, but if you’re into reloading, or don’t mind the thrill and potential dissapointment of not yet finding your store shelf stacked tall with 6mm ARC, well then, the 6mm ARC stands out as a versatile, high-performance cartridge that brings a new level of excitement to the AR-15 platform.

The bottom line is simple – 6mm ARC delivers substantially less recoil compared to the .308, allowing shooters to spot their own shots. Additionally, the AR-15 platform featuring the 6mm ARC has a higher magazine capacity and offers a 30 to 35% lighter-weight package in terms of gun and ammo. Compared to the 5.56, the 6mm ARC achieves significantly better ballistics, with less drop, less wind deflection, and the ability to shoot accurate groups at much greater distances (1000+ yards).

Shooters we speak with are hyped, and for good reason. For reloaders and shooting enthusiasts looking to diversify their firearm collection and explore new possibilities, AR15Discounts.com feels the 6mm ARC is a worthy addition. Its superior ballistics, manageable recoil, and adaptability make it a top contender for any rifle build project, especially if you’re looking to build an AR in something other than 5.56.

6mm ARC