What is the Best Barrel Length For 6mm ARC?

Posted by refactortactical.com on May 11th 2023

What is the Best Barrel Length For 6mm ARC?

Originally posted here.

The Hornady 6mm ARC (Advanced Rifle Cartridge) uses highly efficient, high ballistic coefficient bullets to deliver unprecedented performance from an AR-15/M4 rifle on the battlefield.

Commercial 6mm ARC offerings will feature bullets selected to deliver equally unprecedented performance for hunting and match shooting.

When considering the 6mm ARC round, one important consideration to remember is the 6mm ARC barrel. That can make or break the performance of your rifle.

Is 6mm ARC The Ultimate Long-Range AR Cartridge?

What is the 6mm ARC Good For?

Is the 6mm ARC good for hunting? Accuracy and terminal ballistics are the cornerstones of Hornady Precision Hunter ammunition. Hornady engineers have developed superior, match-grade accuracy hunting loads that allow the 103-grain ELD-X bullet to achieve its maximum terminal ballistics.

The powder used in the Precision Hunter ammunition is clean burning and loaded for consistent shot-to-shot results regardless of the ambient temperature. This attention to detail provides the highest levels of accuracy and performance for the most demanding hunting conditions.

Is The Military Using 6mm ARC?

The identity of the unit that adopted the 6mm ARC is only known as "a notable Department of Defense entity" to the public. A notable Department of Defense Entity in no way means the Department of Defense proper. Special Missions Units can use whatever they desire, purchased with non-attrib funds. Those are funds that cannot be tracked or linked to a specific activity, person, or entity.

An issue that many of our infantry units faced was that the issued ammunition did not lend well to precision long-range fire from the issued M4 carbine or sniper rifle systems. The 5.56 NATO is a poor choice for anything past 300 yards, and moving to the 308 WIN only offers a marginal improvement in ballistics. With the significant weight increase in both firearm and ammunition, the juice wasn’t worth the squeeze. The 6mm ARC exists (and will thrive) because it solves this problem.

Why would select units within the military adopt the 6mm ARC? It has to do with studying and understanding our near-peer threats. Studying not only their small arms capabilities but their tactics as well. For example, the Taliban in Afghanistan knew that most of our military used the 5.56 NATO round, so if they kept their engagement distance to around 600 yards, there was no real need for them to worry about our small arms fire.

Knowing that went into the decision-making process for adopting the 6mm ARC. The unit that adopted that round can now make devastatingly accurate shots out past 600 yards with a lightweight AR-15 patterned weapon system. There was now no need to move into a heavier AR-10 rifle chambered in 308 WIN.

6mm ARC Compared to Other Cartridges

How does the 6mm ARC bridge the gap between the other well-known and well-proven cartridges?

6mm ARC vs 6.5 Grendel

The 6mm ARC delivers comparable performance from a wider array of loads, making it a more versatile choice. The terminal ballistics of the 6mm ARC outperform the 6.5 Grendel at distance.

6mm ARC vs 308

The 6mm ARC delivers substantially less felt recoil allowing shooters to call their own shots. The 6mm ARC is also lighter in weight compared to 308 and boasts a higher magazine capacity.

6mm ARC vs 5.56

The 6mm ARC ballistics outpace the 5.56. With a flatter trajectory, the ability to buck the wind better, and hold tighter groups out to 1,000+ yards make it a far better performer than 5.56 when shooting out past 300 yards.

6mm ARC Ballistics | How Fast is the 6mm ARC?

The Hornady 6mm ARC cartridge was developed to fill the gap between the 5.56 and 308 WIN cartridges. Typically to get the velocity and energy of a 308 in an AR15 package, you had to get into a larger AR10 patterned rifle. 6mm ARC allows you to stay in an AR-15 platform along with increased velocity and energy on target out to 1,000 yards…and beyond.

6mm ARC Ballistics Chart With Real World Data

Hornady 108 grain ELD with a 100-yard zero fired from an 18" barrel at a muzzle velocity of 2,635 fps.

Range (yards)Velocity (fps)Elevation Hold (MILS)
200 yards
300 yards
400 yards
500 yards
600 yards
700 yards
800 yards
900 yards
1,000 yards
1,100 yards

What is the best barrel length for 6mm ARC

There are different lengths of 6mm ARC barrels available, each with its own advantages and disadvantages. When choosing a barrel length for your firearm, it’s important to consider what you want to achieve with it.

For example, you’ll want maximum accuracy and range if you’re a long-range shooter or hunter. Longer barrels (over 20 inches) will provide superior muzzle velocity. A higher velocity will improve your accuracy and range because the bullet can travel further before gravity pulls it off course.

On the other hand, shorter 6mm ARC barrels offer less range and velocity, but they are lighter and easier to handle. This maneuverability makes short to medium-length barrels better for combat, home defense, and other situations where speed and mobility are important.

Common 6mm ARC Barrel Length Options

  • 16-18 inches: A good choice for mid-range combat or hunting, this barrel length provides enough velocity to get the job done.
  • 20 inches: This length is ideal for prey or target shooting, with an impressive velocity that can help you hit your mark.
  • 22 inches: If you want even more velocity, consider a 22-inch barrel. You’ll get a bit more speed than with a 20-inch barrel.
  • 24 inches: For maximum bullet velocity and accuracy at distances over 500 yards, go for a 24-inch barrel.

No matter your barrel length, the 6mm ARC rounds have a high ballistic coefficient. This means that the bullets can maintain their velocity over longer distances. As a result, the bullets can hit targets with significant force at distances greater than 500 yards.

Faxon Gunner Barrel

Who Makes The Best 6mm ARC Barrel?

Faxon has been in the rifle barrel game for a while now and knows a thing or two about optimizing barrels for peak performance and longevity. So it’s no wonder their 6mm ARC barrels are some of the best in the industry.

Faxon Match Series 16" Gunner 6mm ARC Barrel

The Gunner profile is a blend of two of the best-performing profiles of all time, Gov’t and Pencil. Faxon’s Gunner profile combines the durability of the Gov’t profile with the weight savings and maneuverability of the Pencil profile.

The Gunner profile brings the balance of the rifle back towards the shooter’s body, limiting fatigue, and allowing for shooting, training, or hunting all day long.

Manufactured in-house from gun-barrel-quality bar stock, the Match Series starts with 416-R in 5R rifling. 5R is a hybrid rifling, with lands opposite grooves and reduced sharp angles that reduce jacket deformation increasing velocity and easy cleaning.

After rigorous testing, this 6mm ARC barrel is Nitride treated inside and out, locking in the bore, improving barrel life, and keeping the elements at bay.


$235.00 at Faxon Firearms VIEW DETAILS
Prices accurate at time of writing

Faxon Match Series 6mm ARC Barrel Specs

  • Barrel Material: 416R Stainless Steel
  • Barrel Type: 5R Button Rifled
  • Barrel Caliber: 6mm ARC
  • Barrel Twist: 1:7.5 twist rate
  • Barrel Length: 16"
  • Barrel Profile: Gunner
  • Barrel Gas System: Mid
  • Inside Finish: Salt Bath Nitride
  • Outside Finish: Salt Bath Nitride
  • Muzzle Thread:5/8-24 TPI
  • Gas Block Diameter: .750"
  • Gas Block Journal Length: 1.9"
  • Barrel Extension: M4, Nickel Teflon Coated
  • Weight: 1.57 lbs
  • Magnetic Particle Inspected
  • Recessed Target Crown

What is the Best Twist Rate for 6mm ARC?

Early testing by Hornady engineers indicates a 1:7.5 barrel twist rate is ideal for stabilizing the different 6mm ARC loads, which is why Faxon Firearms ensured their 6mm ARC barrels were consistent with that spec.

Pencil. Gunner. Flame. From lightweight to true prevision. See what makes Faxon barrels the best in the industry.

Is 6mm ARC bolt the same as 6.5 Grendel?

The short answer is yes. The 6mm ARC BCG can be used in a 6.5 Grendel weapon. Faxon Firearms manufacturers a bolt and bolt carrier group for the 6mm ARC. If you’re building a 6mm ARC rifle or upgrading components on a stock weapon, you can’t go wrong with the Faxon Firearms 6mm ARC BCG.


$165.00 at Faxon Firearms VIEW DETAILS
Prices accurate at time of writing

Faxon Bolt Carrier Groups are Superfinished to reduce friction, increase the smoothness of operation, and reduce fouling. The 6mm ARC BCG from Faxon is full-Auto rated and maintain the trip for full-auto fire control groups and new multi-stage trigger systems. Gas keys use grade 8 fasteners and are fully staked for a lifetime of service.

6mm ARC BCG Specs

  • Type II (.136") bolt
  • 9310 Tool Steel Bolt
  • Full MIL-SPEC Heat Treatment
  • Shot Peened to MIL-SPEC
  • Magnetic Particle Inspection (MPI)
  • Back of Lugs Chamfered for Reliability
  • Spring, Insert, & “Crane" O-Ring Installed
  • Salt Bath Nitrided Bolt & Carrier
  • S7 Extractor
  • Superfinished Carrier Body
  • Full Auto Compatible
  • Forward Assist Serrations

What Rifle Shoots 6mm ARC?

The 6mm ARC is most commonly known for being used in AR-15 platforms, but there are a few bolt action rifles chambered in 6mm ARC as well.

American Tactical Imports 6mm ARC Rifle


Prices accurate at time of writing

Savage Arms 110 Tactical 6mm ARC Rifle


$734.30 at Kentucky Gun Co VIEW DETAILS
Prices accurate at time of writing

6mm ARC Ammo Availability

Currently trying to source 6mm ARC ammo is a bit of a challenge. I’ve found it at a few smaller online shops, but with the shipping costs as much as the ammo itself, it’s a no-go for me. Your best bet is to sign up for in-stock notifications at all the retailers that will be stocking it.

There is 6mm ARC to be had in larger quantities as well if you’re willing to dish out your hard-earned coin.

6mm ARC magazines on the other hand can be found pretty easily and for affordable prices. Your best bet is to find them at AT3 Tactical and GunMag Warehouse. They will more than likely be found under the 6.5 Grendel magazines since both the Grendel and ARC cartridges use the same magazine.


$13.99 at GunMag Warehouse VIEW DETAILS
Prices accurate at time of writing


The 6mm ARC is a bad-ass round. It remains supersonic past 1,000 yards, G7 ballistics are amazing for its size, it’ shoots roughly 2 mils flatter than 308 at 850 yards, and smokes the 6.5 Grendel.