News|Industry News

Over the years in the firearms market the move hasn’t been towards innovation in certain aspects but, refinement of the AR-15 platform and its cartridges. Seeking to optimize the platform. With this refinement of the platform it has turned the AR-15 from a Whiskey with full body and nice finish to a Whiskey with a full body, subtle notes of flavor with a smooth finish. Hornady looks to take advantage of these refinements by wrapping them all up in their new 6mm ARC (Advance Rifle Cartridge) round. Hornady sees the new 6mm ARC round as the cartridge to take the AR-15 platform to new heights.

History Behind 6mm ARC

The 6mm ARC was born out of an DoD (Department of Defense) contract for it’s multipurpose combat rifle program (MCRP). The contract was looking for the answer of how do you maximize lethality while maintaining the M16/M4 platforms already in use.

Hornady took this challenge head-on. Initially, Hornady investigated optimizing the 6.5 Grendel for MCRP contract but, Hornady ballisticians found limitations in the 6.5 Grendel round when it came to terminal velocities and defeating barriers at distance. Hornady searched for that sweet spot. Ballisticians researched everything from .224 Valkyrie to 6.5mm bullets. They found the majority of shooters where finding success in with 6mm cartridges. 6mm provided great ballistics, terminal velocities, and impact on target. Hornady believe they found the sweet spot with 6mm and looked forward to optimizing the caliber.

The 6mm ARC was the bleeding edge when it came to the benefits of the AR-15 platform yet, maintaining comparable ballistics and terminal performance of an 7.62 NATO cartridge.

6mm ARC

The new 6mm ARC is based off of the 6.5 Grendel. It is not just a necked down 6.5 Grendel, the engineers at Hornady made some adjustments to optimize the case. It shares the same .441” diameter case head with Grendel and Russian .220. The neck has been moved down to accommodate loading the lengthy 6mm round. Shoulder has length has been adjusted as well. It shares a thicker .059” rim of the Grendel. Which is larger than .0.38” rim of 5.56 NATO. Since the 6mm ARC uses the same case head diameter as 6.5 Grendel they can both use the 6.5 Grendel BCG.

The 6.5 Grendel was designed from .264” diameter projectiles running between 95 to 144 grain weight. The 6.5 Grendel shines with weights between 107 to 123 grain weight. The 6mm ARC utilizes .243” diameter projectiles with a grain weight between 103 to 108 grain weight. Again, Hornady seeking to completely optimize the 6mm round. As, stated before the 6mm ARC was designed to optimize ballistics and terminal velocities compared to other AR-15 cartridges.

6mm ARC Ballistic Characteristics

Hornady’s 6mm ARC was designed to outperform 5.56 NATO and have comparable terminal velocities and ballistics to 7.62 NATO. The smaller 5.56 NATO maxes out at 500-600 yards with low impact energy upon target. While the 7.62 NATO provides better ballistics and energy but suffers over 1,000 yards. The 6mm ARC offers greatly enhanced ballistics and terminal velocities compared to 5.56 NATO while weighing 30% less than an AR-10 platform.

Hornady tested 6mm ARC ELD March, 5.56 ELD Match, and .308 ELD March against each other to see how 6mm ARC stacks up.

During the testing all rounds where shot out of 24” barrels of their respective rifles in controlled settings. The data covers trajectory, velocity, and recoil comparison. When it comes down to it the 6mm ARC shot flatter, had greater velocity and impact energy on target, and less recoil. The 6mm ARC even has the ability to say supersonic well past 1000 yards.

Below are the charts and metrics on Hornady 6mm ARC. Also, included is how 6mm ARC surpassed other AR-15 cartridges from Hornady.

How the 6mm ARC surpasses the others

.308 Win

• The 6mm ARC delivers substantially less recoil allowing shooters to spot their own shots.
• The AR-15 platform features a higher magazine capacity.
• The 6mm ARC offers a 30 to 35% lighter-weight package (gun and ammo).


• The 6mm ARC achieves substantially better ballistics than the 223/5.56. It delivers less drop, less wind deflection and the ability to shoot accurate groups at much greater distance (1000+ yds).

.224 Valkyrie

• The 6mm ARC gives hunters the ability to successfully hunt varmints and deer.
• The 6mm ARC produces a larger splash signature that allows shooters to self-spot impacts and make rapid adjustments.

6.5 Grendel

• The 6mm ARC delivers comparable performance from a wider assortment of bullets, making it a more versatile choice.

6.8 SPC

• The 6mm ARC is a better long-range performer.

Ammunition Types

Currently, Hornady offers the 6mm ARC in three different load outs: 6mm ARC 105 gr Hornady Black, 6mm ARC 108 gr ELD Match, and 6mm ARC 103 gr ELD-X Precision Hunter.

Industry Adoption

As, of right now 20 companies are building rifles, barrels, and BCG’s for Hornady’s new 6mm ARC. The heavy hitter names include Barrett, Proof Research, Brownells, Lantac, Noveske, Christensen Arms, CMC Triggers, Geissele, NEMO Arms, and many more. Hornady has the industry heavyweights on its side now it’s down to if this round will gain traction within the community.

Here is the complete list of companies building 6mm ARC rifles and products.

• Adams Arms
• APF Armory
• Barrett
• Brownells
• Christensen
• CMC Triggers
• Geissele
• Howa
• Lantac
• Mossberg
• Noveske
• Odin Works
• Proof
• Radical Firearms
• SanTan Tactical
•Uintah Precision
• Wilson Combat


Within the industry the last few years it has been about the refinement and optimization of the AR-15 platform and its cartridges. The release of the 6mm ARC only expands the capabilities of the platform to the point where 6mm ARC becomes the bleeding edge between AR-15 and AR-10 platforms. While not having the need to jump up to the AR-10. Only time will tell how it all plays out and how the industry and community take to the round.

Your Thoughts

What do you think about the new 6mm ARC? Do you think it will be widely adopted or just another niche round? Let us know in the comments below.

Thanks For Reading

If you enjoyed this post, hit that like button, share it a friend, and subscribe. If you have any suggestions, ideas, or comments. Please feel free to drop a comment. Be Humble. Train until only savagery remains and stay deadly ladies and gents.

Leave a Reply