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AR-15 Rifles

AR-10 Redesign: DPMS GII Review

by James Tarr   |  August 4th, 2014 5

DPMS GII_FMost gun magazines are filled with reviews of slightly tweaked, compact, long-barrel or fancy-colored versions of existing designs. I know because I’ve written a lot of those reviews, and it can be very difficult to find colorful adjectives to celebrate mediocrity. So it is a distinct pleasure to be able to write up a new firearm that is innovative and exciting: the DPMS GII. While the entire GII line is new, I’ll be focusing on the Recon model. But before we go there, let’s first take a look at exactly what the DPMS GII is.

The GII is the second generation of DPMS’s .308 AR (LR) line. DPMS isn’t the only company that has had a lot of success selling versions of Eugene Stoner’s AR-10, which he designed prior to the AR-15, but that didn’t stop it from trying to develop something better.

I’m a big fan of the AR-15 but have never been interested in upsizing that design to chamber the .308. Why? ARs in .308 are noticeably bigger and heavier than 5.56 guns, so much so that they handle much differently. And .308 ARs tend to be much more ammo sensitive than 5.56 ARs.

Not anymore.

The engineers at DPMS studied the design of the AR-10, which is more than 50 years old, and decided there was no reason they couldn’t improve and modernize it. And they have succeeded. The GII isn’t just a tweaking of the venerable AR-10 design—DPMS has turned the .308 AR world upside down.

To offset the recoil impulse of the .308 cartridge, Stoner in 1956 used a big, heavy bolt carrier. But after nearly 60 years of research, engineers have realized that a big bolt carrier isn’t necessary. The heart of the new GII is its redesigned bolt carrier, which has the same outside diameter as a 5.56 bolt carrier and weighs a full half-pound less than a standard .308 bolt carrier. If you compare all three types of carriers, the GII’s bolt carrier group in size is about midway between a .223 and standard .308.

The gas tube of the GII is the same height off the bore as you’ll find with a 5.56, which is new for a .308 AR. While the barrel nut is longer and threaded differently than in other .308s or 5.56s, it has the same outside diameter as a 5.56 barrel nut, which means the GII accepts most handguards designed to work with a 5.56 barrel nut.

The bolt carrier has a redesigned gas key, but what draws the eye is the bolt. In comparison with the narrower bolt carrier it now looks huge, and it has been completely redesigned. It features improved geometry, with rounded lugs to relieve stress lines, and most importantly, the GII bolt now has dual ejectors to improve reliability.

The extractor is also all new. Not only has the shape been slightly changed to improve extraction, but also GII extractors are made of some über-tough proprietary steel the name of which DPMS wouldn’t divulge.

Much of the effectiveness of an extractor has to do with its tension, and after much testing, the engineers at DPMS have gone with a simple black nub of elastomer to provide the tension for their extractor.

Nicknamed the “tactical Skittle,” this little piece of rubber worked best and lasted longest of everything they tried—as in tens of thousands of rounds. There are four new patents on the GII’s extractor and spring alone.

Both the upper and lower are forged aluminum. The lower receiver has the same dimensions as a 5.56 receiver from the back to the rear of the mag well, and it takes all standard AR trigger parts. A steel feed ramp has been inserted into the lower receiver, which allows for a lighter, smaller barrel extension. The lower features an integral oversize trigger guard, and the magazine well has been flared and beveled to facilitate quicker reloads. The ejection port has been lengthened for more consistent ejection. A glance at the case deflector behind the ejection port shows that it has been redesigned as well.

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The GII is currently offered in six variants: a 16-inch lightweight AP4 carbine, 16-inch Recon, 16-inch MOE, 18-inch SASS, 20-inch Hunter and 24-inch bull barrel. The AP4 weighs a mere 7.25 pounds, but what caught my eye at Gunsite (where the Freedom Group debuted the GII) was the Recon version.

The GII Recon features a 16-inch medium-weight bead-blasted stainless steel barrel with a 1:10 twist, mid-length gas system and low-profile gas block, tipped with an AAC Blackout flash hider. It comes standard with Magpul MOE collapsible stock; grip; flip-up sights; a carbine-length aluminum quad-rail handguard that free-floats the barrel; and a two-stage, match-type trigger that provided a crisp 4.5-pound pull.

To the eye and in the hand, the GII looks and handles like an AR-15, something no AR-10 has been able to say since Stoner’s original lightweight version. In fact, I actually had gun store employees pick up the rifle and think it was a .223, until they saw the big mag well. This reduction in size—lighter bolt carrier, shorter receiver—means a huge weight savings.

The GII AP-4 at 7.25 pounds weighs more than a pound less than the original AP-4 and is fitted with a muzzle brake. The Recon, which has a quad rail, slightly thicker barrel and Magpul furniture, weighs 8.5 pounds—still a lightweight in the .308 AR world.

Considering the lower overall weight and the lighter bolt carrier, most people would assume that felt recoil would be much more than that of a standard AR-10. I did. But every writer who shot the new guns at the Freedom Group event found the exact opposite to be true. How can this be?

Felt recoil has as much to do with the reciprocating weight in your semiauto as it does with the power of the cartridge and the weight of the gun. With a bolt carrier that is only marginally heavier than that of a .223, there is much less reciprocating weight in the GII. With half a pound less metal bouncing back and forth with each shot, felt recoil was on par with a 6.8 SPC fired out of a seven-pound AR-15. It’s definitely more than a .223 but noticeably less than what you’d expect from a light .308.

At the writers’ event we were doing full mag dumps from the offhand position. This is a testament not just to how controllable the rifles are during rapid fire but to how light they are. Try keeping a standard .308 AR up to your shoulder through an entire magazine without getting the shakes.

The 7.25-pound AP-4 with its muzzle brake recoiled ever so slightly less than the 8.5-pound Recon. However, muzzle brakes make loud guns even louder, and I don’t like the looks of the one on the AP-4.

The lighter bolt carrier of the GII also got me thinking. The AR is a gas-powered gun. Expanding gases are directed from the barrel back into the receiver to push the bolt carrier group backward, cycling the action.

Rifles in .308 operate at pressures only slightly higher than those in .223, and yet the bolt carrier group of an AR-10 is much heavier than that of an AR-15. If you’re firing very light or very heavy bullets, or using a powder with an unusual burn rate, your AR-10 may not run because it needs a certain pressure at the barrel’s gas ports to cycle that big, heavy bolt carrier. That is why .308 ARs are traditionally much more ammunition sensitive than .223s.

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With the GII, I believe DPMS may have designed a gun that is much less finicky, specifically because the bolt carrier of the GII weighs a half-pound less than that of a standard .308 AR. Everything I saw tends to point in this direction.

At the Freedom Group event, I was one of a group of writers who put more than 3,000 rounds through nine Recons and AP-4s in an afternoon, and we couldn’t get our rifles to choke once. Fellow writer Tom Beckstrand pounded 340 rounds through the same GII Recon as fast as he could load mags, and he didn’t have a single malfunction. Admittedly, we were using only two types of Remington ammo: 168-grain boattail hollowpoints and a 150-grain load (the specifics of which I can’t remember).

I wanted to test my theory that the GII was more ammunition blind than a standard AR-10, so when I got my test rifle at home I secured as much ammo as I could with bullets in a wide variety of weights and power—from the 120-grain Winchester PDX1 to the soft 125-grain Hornady Custom Lite load and all the way up to 175-grain match loads from Black Hills. For testing I used the provided magazine from DPMS, one from Magpul and some new 10-round magazines from D&H Industries.

I wasn’t able to do an exhaustive endurance test on the GII, but I put at least 100 rounds of each type of ammo I tested for accuracy through the rifle without any problem. I’ve seen clean and new .308 ARs choke on fresh factory ammo simply because the round’s pressure curve didn’t fit that gun’s gas system, so that kind of reliability, with a wide range of bullet weights, is saying something.

For accuracy my GII preferred medium-heavy bullets. While the 120-grain PDX1 and 125-grain SST still shot less than 1.5 m.o.a., heavier bullets made tighter groups. An engineer from DPMS said the stainless barrels in the Recon were averaging between 0.75 and 1.5 m.o.a. accuracy, depending on the gun. Mine was averaging just over one m.o.a., which is plenty accurate for a rifle of this type.

The only complaint I—and just about everyone else who saw or handled the GII Recon—have is about the handguard; it’s too short. Longer handguards are in fashion because they are functional. Not only do they allow you to place your support hand farther out on the gun, but also they provide more real estate for anything you might want to mount on the rails: sling swivel, vertical foregrip, bipod and so forth.

The carbine-length quad rail handguard on the GII Recon doesn’t even cover the gas block, but because the outside diameter of the GII’s barrel nut is the same OD as a 5.56 barrel nut, any handguard that slips over a standard .223 barrel nut should fit on the GII.

Not so long ago, there used to be such a thing as a “big-bore battle rifle.” In that category you could find the M14, HKG3/91, FN FAL and Stoner’s original lightweight AR-10, which tipped the scales at 7.25 pounds. While those rifles haven’t disappeared—you can find refurbished M14s and the .308 AR SASS being used by the military in designated marksman or sniper roles—the concept of a shoulder-fired .308 used for combat has. Why? Once you get past caliber selection, the answer mostly has to do with weight.

In the modern military world, nobody carries just a rifle. First they attach a sling, then an optic, maybe a flashlight and vertical foregrip, and perhaps some sort of IR laser, mount for night vision, suppressor—or all three. That’s an additional two to four pounds of weight.

Considering semiauto .308s are usually pounds heavier than .223s to start, it’s no wonder they’re being considered only for semi-stationary roles. While I don’t see the military ever switching from 5.56 back to 7.62, kudos to the engineers at DPMS for actually making a .308 semiauto rifle that doesn’t require weightlifting to wield.

I see a lot of 3-Gun shooters who love Heavy Metal division (.308 rifles) rushing toward the GIIs simply because of weight—not to mention hunters who chase bigger critters than the .223 can handle.  If long-term field testing shows the new GII design offers a marked improvement in reliability over the standard .308 AR system (as I suspect it will), expect DPMS to have problems keeping up with demand.

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