There are two types of firearms that I enjoy shooting: precision rifles and AR15s. 

The struggle for me was that there was never a great way to combine those loves. The .223/5.56 cartridge is very versatile, but it's light, gets blown around in the wind, and the small case limits its capability for long-range shooting. 

Many wildcat-type cartridges have aimed to turn the AR15 into a long-range hammer, but they all have their own issues, until now.  

The 6mm Advanced Rifle Cartridge (ARC) was designed to increase the capabilities of the M4/AR15 platform beyond what the 5.56 could provide, and it does that with incredible results.

The 6ARC is popular among long-range precision shooters, hunters, and tactical applications. 
 

Table of Contents

What Was 6ARC Made For? 

Troops in the Global War on Terror (GWOT) consistently encountered situations where they needed more range than their 5.56 M4 carbines could provide; the commonly accepted range of that platform was about 400 yards. This led many soldiers to carry the SR25, a large-frame AR10-style rifle chambered in .308 Winchester. It gave the soldiers the range they needed, but it had its own significant drawbacks. 

The SR25 rifles were large and cumbersome to carry. They required the soldiers to change their gear to accommodate the larger magazines and had to carry less ammo. 

This led the geniuses at Hornady to start developing a nimble and sleek system like the 5.56 AR15 but with the range and capability of the .308 AR10. 

Development of the 6ARC 

I followed the development of the ARC very closely, listening to every Hornady Podcast and reading any article I could find about the round. 

I wanted this to be the " Holy Grail" round I had been searching for that offers bolt gun-level performance for a semi-auto gas carbine. 

6ARC was developed by the ballisticians at Hornady, the same folks that brought us incredibly popular rounds like the 6.5 Creedmoor. 

The 6ARC project was ambitious for two key reasons. First, it involved developing ballistic ammunition similar to the .308 Winchester. Second, the ammunition had to work in the small-frame M4/AR15 platform, not the larger SR25/AR10 rifle. 

The 6mm ARC ammo was designed around an 18" barrel; an 18" AR15 is roughly the same overall length as a 16" AR10. Once the early testing results were released, it was clear that the 6ARC was something special. It exceeded 5.56 in every metric and rivaled .308 in key categories. The 6 ARC checked all of the boxes it set out to. 

The 6ARC was the solution to a problem many people had wanted answered, and it was released to the public in 2020. Unfortunately, a certain worldwide event set the firearms industry ablaze that year: 

  • There were no guns 
  • No ammo 
  • No reloading components 

 
However, I still got on waitlists for barrels, bolts, and reloading dies (and brass goblin’d any brass I could find). 

6mm ARC Ballistics  

The primary advantage of the 6mm ARC is its excellent ballistic performance. The cartridge can achieve high velocities and maintain a flat trajectory, making it ideal for long-range shooting. Its high ballistic coefficient (BC) bullets offer superior wind resistance and energy retention compared to other cartridges in its class. 

The 6mm ARC cartridge has 54% less recoil than the .308, is 30% lighter weight than the SR25 loadout, and has better magazine capacity. Thanks to its highly efficient 6 mm projectiles, the ARC can make consistent impacts out to 1000 yards with less bullet drop than the .308. 

Once I finally got my 6 ARC rifle assembled, I quickly took it to the range and tested its capabilities for myself, and I was blown away. It felt like shooting a .223; there was almost no recoil. Despite feeling familiar, I knew the round had a lot more to offer. With my 18" rifle, I was effortlessly getting first-round impacts out to 700 yards, the maximum range I had available. 

6ARC Bolt Action Rifles  

While the Advanced Rifle Cartridge was built for the AR15 platform, it can unlock even more performance when used in a bolt-action rifle. 

During Hornady's testing, they developed two different standards for the round: gas gun and bolt gun loads. They found that the bolt actions could be pushed to higher pressures due to their thicker chamber walls and larger bolt lugs. 

Using 6ARC in a bolt action allows you to bump up the pressure to 62,000 PSI, which is 10,000 PSI greater than the gas gun loads. 

That extra "oomph" takes the 6ARC to the next level of performance, making it an excellent contender in precision shooting and hunting scenarios. 

Why Use 6ARC?  

We've talked a lot about the 6mm ARC's long-range performance and ability to be used in an AR15 or bolt-action rifle, but what are people actually using the 6 ARC for? 

I adopted the 6ARC early to use in precision gas gun matches and to ring steel at distances I previously thought impossible with an AR15. Others are putting the round to the test in other disciplines. 

Hunting  

The 6ARC quickly earned a spot in most precision hunters', predator hunters', hog hunters', and varminters' safes. It can be loaded with extremely light, high-velocity bullets ranging from 55 to 90 grains, making it excellent for use on smaller game animals like prairie dogs, raccoons, coyotes, and more. 

The round can also use heavier bullets from 100-115 grains to down medium/large game animals like deer, antelope, and feral hogs. 

The efficiency of the case design also allows 6ARC to carry enough energy to hunt ethically with short barrels. Hunters can use barrels as short as 12.5" to harvest game effectively with a small, lightweight, low-recoiling rifle. 

I have yet to trek out to the wilderness with my 6ARC to put meat in the freezer, but that may be my next journey with this incredible cartridge. 

Tactical   

The 6ARC was designed for special Department of Defense (DoD) units. The cartridge is incredibly ballistically efficient and provides extended range and energy compared to other intermediate rounds. 

Competition  

6ARC really elevated the capability of the AR15, which made the round an instant top-tier pick for gas gun competitions like: 

  • Precision Rifle Series (PRS) Gas Gun Division 
  • National Rifle League (NRL) 
  • Quantified Performance (QP) 
     

Competitors could make hits on smaller targets at longer ranges more effectively without using unwieldy large-frame rifles. 

The cartridge has also seen adoption in bolt-action matches, which were formerly dominated by very high-velocity "barrel burner" rounds like the 6 Creedmoor or 6 Dasher. Lately, the trend has been to use lower-velocity and lower-recoiling rounds so that shooters can more easily spot bullet trace and see splash from misses to make corrections. Enter the 6ARC. 

The ARC can achieve muzzle velocities around 2750 FPS with the high BC 108-grain bullet, which is in line with common loads the top PRS shooters are running now, making it a great choice for long range matches. 

Suppressors for 6ARC  

If I'm shooting a rifle, it's going to be suppressed. 

When you add a suppressor to the 6ARC, it really improves the platform. Of course, you reduce the decibels and protect your hearing, which is essential, but you also make the rifle even more effective. 

Suppressors increase velocity and reduce recoil, which is ideal for a precision-oriented rifle.  

Early adopters of the 6ARC were using .30 caliber silencers. They worked well for the round, but manufacturers have recently built 6mm silencers optimized to harness the 6ARC. 

6mm Silencers to Check Out: 

CAT NOAH  

HUXWRX Flow 6K  

Otter Creek Labs Polonium  

CGS SCI-SIX  

AAC Ranger 5  

How to Setup Your 6ARC  

I have spent a lot of time tinkering and testing with 6ARC rifles and suppressors and have found some helpful tips to ensure you get the most out of your next build. 

Setting up your AR15 for suppressors isn't difficult, and you can save some time and money by getting the right components the first time instead of swapping out parts down the road. 

6ARC is gassy. The round needs to generate a lot of pressure to achieve supersonic velocities. This is done by creating a lot of gas to build pressure in the barrel. We can combat that gas with a few parts to make shooting the ARC a breeze. This was particularly important to me as a lefty, as my face is right by the ejection port. 

Recommended 6ARC Components:  

  • Adjustable Gas Block: This will allow you to tune the gas coming back into the action, reducing the excess gas and making your rifle smoother and cleaner.  
  • Heavy Buffer: A heavier buffer, like an H2 weight, will keep the bolt locked in battery longer and allow the barrel pressure to drop. That means less ejection port noise and less recoil.  
  • Gas-Defeating Charging Handle: Using a charging handle designed to keep any residual gas out of your face, like the SilencerCo GDCH and Radian Raptor SD, can improve your shooting experience.  
  • Low Backpressure Silencer: A low backpressure suppressor will limit the amount of gas coming back into the gun. I highly recommend it for 6ARC gas carbines. 

My 6ARC Build 

I was an early adopter of the ARC. I followed its development, obtained some of the first components available to the public, and tested the cartridge and rifles thousands of times. 

The build that I've settled on (for now) is as follows: 

Barrel 

I'm using the Noveske 18" ARC barrel. It is a precision stainless steel barrel that delivers excellent accuracy. I replaced the included gas block with an adjustable one, delivering excellent performance. The Noveske is threaded in 5/x24, which is typical for 6ARC, and allows me to swap suppressors easily. 

Handguard 

This rifle is designed for precision roll, so I wanted a way to swap out accessories like tripods and bipods quickly. That meant using an ARCA rail. The VLTOR Freedom rail has a built-in ARCA rail and lets me slide my MDT Ckye-Pod on and off depending on the environment I'm shooting in. 

Receivers 

Aero Precision released one of the coolest builder sets I've ever seen, the "Jurassic Hunter" and I couldn't resist. As a lover of Tiger Stripe, I scooped up these matching receivers as the foundation of my build. They are well-machined, have no play between them, and look outstanding. 

Bolt Carrier Group 

This system uses the JP Enterprises Full Mass Operating System (FMOS) BCG. It adds some weight and mass to keep the bolt locked in the battery longer and has more bearing surface, which helps smooth the stroke of the BCG. 
 
Charging Handle 

To stick with the Aero receiver set, I decided to test out the Aero Breach Charging Handle, it has been excellent for keeping gas away and the ambi levers make it easy to actuate.  

Buffer System 

I installed a VLTOR A5 buffer tube and settled on the A5H2 buffer weight, this helps with feeding reliability and further slows down the bolt for less gas and sound at the ejection port. 

Stock 

Stock choice was important for this one; it needed to be adjustable for the length of pull and comb height but have no movement on the buffer tube. I opted for the LUTH-AR MBA-3 Carbine stock. It locks down with no wiggle, has all the adjustment I want, and has a built-in bag rider. 

Trigger 

I need all the help I can get hitting targets, and a good trigger makes that a lot easier. I went with the Geissele Super Dynamic Enhanced (SD-E) trigger; it uses a flat face and crisp break that have helped me stay consistent.  

Grip 

The Black Collar Arms Priapus Grip offers a great blend between a traditional carbine grip and a precision rifle grip, its more vertical and fits my hand well.  

Scope 

Glass is critical for a precision carbine, the Meopta Optika 6 3-18 has excellent clarity, tracks true, and the reticle is usable up close at low power, and gives you graduated holds for longer shots when you dial up the magnification.  

6mm ARC FAQs 

Who makes 6 arc ammo? 

Hornady developed the cartridge and has many ammo offerings. You can also find 6ARC ammo from other major ammunition manufacturers. 

Is 6mm ARC the same as 243? 

The 6mm ARC uses the same projectiles as the .243 Winchester but is a much more efficient design with wider applications. 

Is 6.5 Grendel the same as 6mm ARC? 

The 6.5 Grendel and 6mm ARC use the same parent case and same bolt face, but the 6mm ARC uses higher BC bullets tailored towards precision shooting. 

Conclusion 

I love the 6ARC. 

The 6mm ARC is a versatile and high-performing cartridge that offers significant advantages for hunters, competitive shooters, and tactical users alike. With its excellent ballistic performance, flexibility, and compatibility with the AR-15 platform, the 6mm ARC has quickly become a favorite among shooting enthusiasts. 

Whether you're looking to improve your long-range accuracy or need a reliable round for hunting, the 6mm ARC is worth considering.