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Water Dragon: Grey Ghost 6ARC DRAC

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When people talk about 6mm ARC, they mention the impetus was a DoD project but get cutesy about exactly what part of the DoD it’s meant to serve. While we can’t mention any individual names or unit designations, we can say the guys with the surfer hair who coauthor books upon retirement are behind it. 

Of course, we’re talking about Naval Special Warfare and SEALs.

Water Dragon: Grey Ghost 6ARC DRAC

Like the ammunition itself, this rifle from Grey Ghost Precision was put together for the same — not in a workshop but refined on the range over the span of months by students and instructors of DoD Advanced Sniper courses. 

What you see on these pages isn’t the first version GGP put together, just the first one you’ve seen. This shows in the official name: the Designated Rifleman Advanced Combat System Mod 3 V4, or DRAC. 

In mythology, a Drac was a dragon associated with water and the dangers surrounding it, which seems like a suitable name for a tool for frogs. 

To be clear, much like other Grey Ghost Precision rifles and pistols, a number of DRAC Mod3 V4s are currently in the hands of SEALs but not (yet) in an official “program.” 

Still, if you know where to look, you can catch glimpses of their wares in JSOC and other hands. 

While ostensibly this is a review of a new GGP rifle, with 6mm ARC being so new we’ll also spend some time on the caliber and ballistics. 

We’ll also compare it to the much-shorter 11.5-inch barreled Lantac LA-SF15 chambered in 6ARC we covered back in RECOIL Issue 51, as each rifle represents either end of the spectrum in this caliber.


The practical engagement range of 6mm ARC envelops both 5.56mm and 7.62x51mm, while wearing a shorter barrel and bucking wind better than either.

6mm ARC and 6.5 Grendel have so much in common they’re practically kissing cousins from West Virginia. 

Left to right .300BLK, 6mm ARC, 7.62x39, 6.8 SPC II, and 5.56mm
Left to right .300BLK, 6mm ARC, 7.62×39, 6.8 SPC II, and 5.56mm

In short, they share the same parent case of 7.62x39mm, necked down for a smaller projectile.

It’s more accurate to say that the 6mm ARC is an improved version of 6.5 Grendel, itself an American version of .220 Russian/5.6x39mm, itself a bottlenecked 7.62x39mm. 

The 6mm ARC shares a bolt with the 6.5 Grendel, but neither uses a 7.62.x39mm bolt despite it being the parent case. The 6ARC/6.5 Grendel bolts have a face with a deeper recess to increase extractor engagement and accommodate the thicker rim. 

When 7.62x39mm AR-15s were first developed, most manufacturers hit the “easy button” of using the same bolt face depth as 5.56mm despite the negatives — just one of the many reasons why x39 ARs can be absolute nightmares to get running reliably. 

6mm ARC and 6.5 Grendel ballistically perform close to one another out to about 300 yards.

An 11.5-inch 6ARC doesn’t drop below the speed of sound until 920 yards, and a 16-incher until 1,050.
An 11.5-inch 6ARC doesn’t drop below the speed of sound until 920 yards, and a 16-incher until 1,050.

However, once you get beyond medium rifle ranges, the 6ARC really is a standout — as in supersonic at 1,000 yards in a small package standout.

The 6ARC has a smaller case length than the 6.5 Grendel to accommodate longer projectiles that perform better at these longer ranges, while fitting into the footprint of a standard small-frame AR-15. 


Grey Ghost Precision has never made beer-money guns, because their developmental focus has always been putting sticks in the hands of dirty bearded men, not the Cabela’s crowd. 

GGP exists whether the American civilian market buys their guns or not (though we’re sure it doesn’t hurt) but those with cash in their pocket can still purchase them on the open market. 

The 6ARC GGP DRAC is similar to their other rifles, in that the billet receivers, deep anodizing, and good balance all adds up to something you can immediately tell is high quality as soon as you heft it. Tight tolerances and slick-smooth parts. But 6mm ARC itself has some quirks that warrants some extra attention.  

The heart and soul of any rifle lays in the combination of the barrel and bolt carrier group, and inherent accuracy is derived from how consistently they work together and the fuel you feed it.

The barrel is a carbon-fiber wrapped, 1/7.5 twist, 16-inch PROOF Research with rifle-length gas. It’s threaded 5/8×24 and comes with a Superlative Arms adjustable gas block installed. What makes the Superlative Arms block unique is that it can be used to either restrict or exhaust excess gas, depending on how you set it up (more on this later).

The carrier is the JP Enterprises Full Mass Operating System (FMOS). Machined from 416 stainless steel, FMOS carriers are purported to have twice the bearing surfaces of a Mil-spec bolt carrier for improved alignment and reduced wear in the upper receiver. The bore is roller-burnished to reduce friction, and the entire assembly is finished in QPQ for additional lubricity and wear resistance. 

The JP FMOS bolt carrier is right at home with the Battle Arms Development RACK charging handle.
The JP FMOS bolt carrier is right at home with the Battle Arms Development RACK charging handle.

Similarly, the bolt is a 9310 steel JP Enhanced Bolt Assembly. The locking lugs have machined radii to help better distribute force. JP claims an estimated service life of 60,000 rounds — or more than a baker’s dozen barrel changes. 

This may seem like overkill at first, but the history of stuffing new calibers into AR-15s is rife with broken bolts and disappointment.

We can’t say for certain that a PROOF barrel and Gucci bolt carrier group is needed for 6ARC, but considering PROOF Research was part of the original R&D team (along with Lantac and Hornady), it probably doesn’t hurt. Rifles are getting more accurate and before too long you may see 6ARC bargain barrels, but precision is still something you have to pay for. 

Further screaming “precision” is the Magpul PRS Gen 3 stock and two-stage Timney Targa trigger. We already have machinations of a B5 SOPMOD taking the place of the PRS stock.

The charging handle is a Battle Arms Development RACK, a three-piece, totally ambidextrous affair with generous purchase. The selector is also from Battle Arms Development. The GGP-standard righthand bolt release is also included; it’d be nice to see an ambidextrous magazine release and bolt lock on future iterations.

Battle Arms Development RACK charging handle

The muzzle end of this GGP DRAC is crowned with a SilencerCo ASR flashhider, to which we affixed a SilencerCo Omega 300. 

One of the issues we ran into when testing the Lantac 11.5-inch 6ARC rifle was running out of magnification on the long end and the reticle obscuring the target — the Vortex Razor Gen III 1-10×24 we mounted just wasn’t enough ass at 1,000 yards. 

This time we mounted a first focal plane 3.6-18×44 Leupold Mark 5HD with a Tremor3 reticle, riding in a Spuhr SP-5616 6MIL/20.6MOA mount. The Spuhr was just itching for a miniature red-dot sight on the side. 


It’s taken some manufacturers a considerable amount of time to develop these guns, partially due to spartan ammunition stores and in part because the operation of this cartridge in an AR-15 seems to take more finesse than just throwing a barrel on it.

For the best reliability and smoothest operation, the 6mm ARC seems to prefer a longer gas system and requires less dwell time that more traditional loads, virtually the opposite of 300BLK. The DRAC uses a rifle-length gas system on a 16-inch barrel; Lantac uses a mid-length gas system on a 11.5-inch barrel. Many other barrel lengths available use custom gas system lengths. 

Embrace your mag curves 20-round Brownells 5.56mm, 17-round E-Lander 6ARC, and 20-round CPD DuraMag 7.62x39.
Embrace your (mag) curves 20-round Brownells 5.56mm, 17-round E-Lander 6ARC, and 20-round CPD DuraMag 7.62×39.

Whenever we step out of the realm of 5.56mm in an AR-15, magazines invariably become an issue. Even calibers that purport to use STANAG mags like the .300BLK or .450 Bushmaster perform better with magazines with dedicated followers and mag bodies for the caliber. In some cases, such as with 7.62×39 and 7.62×51, it can take years to come up with a consistent and reliable magazine. The 6mm ARC is no different. Currently, 6.5 Grendel mags are the go-to, and because we’re curious, we tried 6mm ARC in 7.62×39 C-Products DuraMags, which also worked. 

There are now several options, and by the end of the day, we’d like to see magazines made for the specific curvature of the 6ARC as opposed to relabeled 6.5 Grendel. 


Before we hit the range, we populated our Applied Ballistics app and Kestrel with Hornady load data and measured muzzle velocity. We found the AB engine to line up with reality once environmental factors were applied, reinforcing that ballistic math is best performed by a computer crunching numbers rather than a booger eater with a slide rule. 

One nice thing about using rifle-length gas on a 16-inch barrel is that the Superlative Arms gas block can be adjusted with a regular old hex key instead of an extra-long one you’ll lose the second time you take it out. Superlative Arms recommends running the gas block in “bleed off” mode rather than “restrictive” because it more easily accepts a silencer, which increases gas pressure. In practice, both ends of the spectrum will reduce pressure in the system and felt recoil. 

Recoil seems on par or below a 7.62x39 AR, which should be no surprise
Recoil seems on par or below a 7.62×39 AR, which should be no surprise

As the rifle shipped, everything was A-OK with the SilencerCo Omega 300 on and off. We ran into problems trying to further tune the rifle — normally, we’re fans of a high level of customization but with more than 40 settings, you can really eat into your ammo stash simply dialing it in. An FN SCAR-style on/off (or 3-select) would be welcomed here. If it ain’t broke …

The only 6mm ARC ammunition we had available was 108-grain Hornady ELD Match, but what we lost in variety we made up for in quantity, ultimately sending more than 400 rounds downrange. Fortunately, the GGP DRAC shoots lights-out with it. The average of (5) five-shot groups was 0.64 MOA, but we know it can print better because half MOA plates at range weren’t terribly challenging. 

Recoil is heavier than 5.56mm, but far less than a large-frame gas-operated 7.62×51 or 6.5 Creedmoor. You shouldn’t be shocked to hear it’s about on par with 7.62×39 out of an AR-15, appropriate given the parent case. 

The Timney Targa two-stage short trigger worked as advertised, with a bit of slack before the bang. Each stage clocked at 2 pounds each, for a total of 4 pounds of trigger pull. We know not everyone prefers a two-stage trigger, but since this is a standard-size AR lower you can drop in whatever you like. 


Because 6mm ARC performs exceptionally well from short barrels and the velocity gains you traditionally get from longer barrels become mere incremental increases in capability, it’s hard not to let the mind wander. The ballistic difference between 11.5- and 16-inch barrels in 6ARC is about 200 FPS from the muzzle, or an extra 130 yards before the round goes transonic and engagement becomes more difficult (920 yards versus 1,050).

For military use, add in a “Smart Scope” and this represents a shift in capability so large it could be doctrine changing. Imagine a squad where everyone has four-digit or near-four-digit range capability in their hands, in a rifle the same size (or smaller) than they’re currently carrying. With that level of performance, it becomes more about formatting the rifle for the role rather than the caliber. 

Vortex Razor HD Gen III cover
Vortex's 1-10x Razor Gen 3 isn't badass “Smart Scope” Vortex has developed for the Military recently, but it's pretty awesome

The “perfect” barrel length for 6ARC is contested among RECOIL staff, but the spread is under 2 inches. On the civilian side of the market, our barrel lengths are restricted federally due to arbitrary minimums unless you want extra paperwork and hassle crossing state lines. A 13.7-inch barrel with a permanently attached modular muzzle device (see RECOIL Issue 58 for more 13.7-inch build ideas) would work well, but anything in the 11- to 18-inch range is supremely capable. 

Our current limitation on a Goldilocks rifle seems to be optics, and here we’d once again advocate a viable MPVO (Medium-Powered Variable Optic), such as a 2-14x with an offset red dot in the form factor of an LPVO (see “The Optic You Don’t Know You Need” on 


As a precision-oriented rifle, the GGP DRAC is configured with a bias toward accuracy. This should be no surprise, providing a precision stock and more handguard space for bipods, thermal and night vision clip-ons, and other accessories, while accommodating the larger optical footprint that high magnification glass currently requires. The long and short of it is that the rifle looks exactly like this because some SEALs wanted it like this. The DRAC shoots better than the majority of the population is currently capable.

In terms of 6mm ARC, it’s not yet both cheap and plentiful, but at least it’s increasingly available. When we first wrote about 6ARC some year and a half ago, there were scant few companies making parts for it, but times change fast. Even Stag Arms, a more traditional AR manufacturer, has thrown their hat into the ring. 

We don’t yet know when or what the 5.56mm round will be replaced with, and this is far from the first contender in modern history. But whatever the next carbine caliber actually is, it won’t perform significantly better than the 6ARC — not if it stays within the confines of the standard small frame AR-15. It’s not hard to imagine 6mm ARC in a True Velocity polymer case (see RECOIL Issue 54 for behind the scenes at True Velocity).

There’s not much 6ARC can’t do better than 5.56mm, except currently existing in bulk on the shelves of your local gun store. 

With Hornady pushing out ammunition, SEALs doing SEAL stuff with it, and dozens of manufacturers now producing parts, it’s not just a shot in the dark. 

Grey Ghost Precision DRAC Specs:

  • Caliber: 6mm ARC
  • Barrel length: 16 inches
  • Overall length: 37 inches
  • Weight (unloaded): 7 pounds, 14 ounces
  • Capacity: 5/10/17/25
  • MSRP: $TBD
  • URL: GreyGhostPrecision.Com
  • Accessories:
    • SilencerCo Omega 300: $915
    • Leupold Mark 5HD 3.6-18×44 FFP T3: $2,200
    • Spuhr SP-5616: $410
    • Atlas BT46-LW17 PSR bipod: $320
  • Price as configured: ($3,845 + TBD)


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