6mm ARC, By the Numbers
It uses the same Grendel-pattern bolt as 6.5 Grendel and runs in a standard AR-15 lower and upper, which makes it one of the most popular ways to build a precision or hunting AR without moving up to an AR-10.
Why a 1:7.5 Twist
Hornady built 6mm ARC around a 1:7.5 twist so it stabilizes the long 103 to 108 gr match and hunting bullets the cartridge is known for.
| Bullet / load | In a Faxon Match barrel |
|---|
| 103 gr ELD-X | Fully stable |
| 105 gr BTHP | Fully stable |
| 108 gr ELD Match | Fully stable; the reference match load |
Velocity and Barrel Length
Hornady publishes from a 24″ test barrel. Gas-gun loads also run lower than bolt-gun data, so expect your numbers to be lower than the box.
| Load (fps) | 24 (factory)″ | 22 (measured)″ |
|---|
| 108 gr ELD Match | 2,750 | 2,633 |
| 105 gr BTHP | 2,750 | 2,615 |
| 103 gr ELD-X | 2,800 | 2,627 |
Sources: Hornady factory data and Athlon Outdoors’ 22″ chronograph test. Estimates, not Faxon testing.
Every Match Series 6mm ARC Barrel
| Barrel | Profile | Twist / gas | Journal / thread | Weight | MSRP |
|---|
| 12.5″ | Gunner | 1:7.5, carbine | .750″ / 5/8x24 | 1.26 lb | $230 |
| 16″ | Gunner | 1:7.5, mid | .750″ / 5/8x24 | 1.57 lb | $236 |
| 20″ | Heavy Fluted | 1:7.5, rifle | .750″ / 5/8x24 | 2.04 lb | $302 |
| 24″ | Heavy Fluted | 1:7.5, rifle | .750″ / 5/8x24 | 2.95 lb | $308 |
Choose Your Profile
Gunner. Faxon’s Gunner profile puts steel where a barrel needs stiffness, at the chamber and under the handguard, and trims it out front, so you get Government-profile durability with close to Pencil-profile handling.
Heavy Fluted. The Heavy Fluted profile starts with a heavy, stiff contour for precision and cuts straight flutes along the barrel to remove weight and add surface area for cooling, so you keep the rigidity without carrying all of the steel.
What You Need to Build It
Resources: 6mm ARC Barrel Buyer’s Guide • Best 6mm ARC Barrel Length
What Every Match Series Barrel Shares
Every Match Series barrel is machined from 416-R stainless, 5R button rifled, stress relieved, 100% wet magnetic particle inspected, and salt-bath QPQ nitrided inside and out. Each ships with a nickel-Teflon (NP3) barrel extension installed, torqued to 150 ft-lb, pinned, and headspace checked 100%, and every one is full-auto capable. Faxon AR-15 and AR-10 barrels have been voted Favorite Aftermarket Barrel by Shooting Sports Retailer every year since 2022, the Gold Award.
Average ratings, out of 5 stars: 4.9 on FaxonFirearms.com (across this lineup).
6mm ARC Barrel FAQs
What bolt and magazines does 6mm ARC use?
The same Type 2 Grendel-pattern bolt as 6.5 Grendel (.136″), such as Faxon’s 6.5 Grendel/ARC Type 2 BCG, and magazines made for 6mm ARC. Not every Grendel magazine feeds 6mm ARC reliably, so use ones built or tested for it.
What is the best barrel length for 6mm ARC?
It depends on the job. 12.5″ is the compact suppressed choice, 16″ is the all-around hunting and carry length, and 20″ to 24″ get the most velocity for long-range precision. Faxon’s 6mm ARC barrel length guide walks through each.
Which 6mm ARC barrel length should I choose?
Shorter barrels build compact, suppressor-friendly guns; longer barrels add velocity and reach. 12.5″ Gunner: 1:7.5, carbine gas. 16″ Gunner: 1:7.5, mid gas. 20″ Heavy Fluted: 1:7.5, rifle gas. 24″ Heavy Fluted: 1:7.5, rifle gas.
Are Match Series barrels full-auto capable?
Yes. Every Faxon nitrided rifle barrel is full-auto capable. Each product page carries heat guidance: about 12 to 15 rounds a minute indefinitely, about 150 rounds of continuous rapid fire before cooling, and groups open as a barrel heats while point of impact holds.
