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Right on the Mark

by Patrick Sweeney   |  September 23rd, 2010 2

The new DPMS Mark 12 is what the AR-10 should’ve been all along.


One of the biggest complaints about the AR-15 is that it isn’t “enough gun.” Those who want more have always pined for the halcyon days of the AR-10, arguing the merits of Sudanese vs. transitional vs. Portuguese versions of the design. I’ve handled original AR-10s, and let me tell you something: You aren’t missing anything. The earliest guns were lightweight, fragile, finicky and clearly in need of additional engineering. The later ones had some faults corrected, but not all of them.

Since then, we’ve waited a long time for improved-engineered .308 Stoner-system rifles, and now we’re seeing them. Part of that improvement comes from the Army and other branches wanting (or, at least, some units in the branches wanting) a bigger-bore rifle for more reach and oomph.

Mostly, though, we can thank the computer age. When CAD/CAM design software can practically be downloaded to your cell phone and everyone who makes anything does so on CNC machining stations, it gets a lot easier to design, fabricate, test and improve a rifle.

DPMS has stepped into this improved, more powerful AR market with its Mark 12, one of the Panther series of .308 rifles. As you’d expect, it is a scaled-up AR-15 in many regards. There is, after all, no point in reinventing the wheel. So items such as the pistol grip and stock, fire control internals, rear sight and such are standard AR-15 parts.

If you want to change or upgrade your Mark 12, you can do so a lot more easily than if everything were custom. The Mark 12 comes in a hard case, with a cleaning kit, sling and two 19-round magazines. More on the magazines in a bit.

For a long time, DPMS has been using an extruded upper, machined out of 6066-T6 aluminum alloy. On the Mark 12 the company has moved from the full-extrusion look (which I personally found to be a bit, ah, ugly) to a design that is more sculpted.

As DPMS has been making–and selling–the old design, clearly a lot of customers liked it. But thanks all the same to DPMS, because I prefer the new shape. The left side is still the plain sidewall extrusion, but the right side now has a spring-loaded dust cover on the ejection port and a forward assist. The forward assist also acts as an ejection deflection “lump” that keeps left-handed shooters from getting “brass face.”

To accommodate the .308 cartridge, and the bolt and carrier it requires, DPMS has scaled the .308 receivers up from the AR-15 size, and the top deck of the lower receiver shows it. Milled from billet 6061-T6 aluminum, the top edge of the lower has a lip running the length from the magazine well area to the buffer tube loop. This edge matches the contour of the upper and adds rigidity to the lower to help deal with .308 recoil.

Both upper and lower, once they have been mil-spec hard-coat anodized, are given a black Teflon coating.

The sights are a folding A2 type on the rear and a folding front that is built into the gas block. Both are from Midwest Industries, a solid and well-known AR sight provider.

The railed fore-end free-floats the barrel and covers the gas tube. Yes, the Mark 12 is direct-impingement, not a piston gun. You piston fanatics are just going to have to be patient.

The barrel is 18 inches long and has a 1:10 twist, and DPMS nicely avoids the problems of sourcing a hard-chromed .308 barrel by making the Mark 12′s out of 416 stainless and then coating it with black Teflon.


Larger cartridge, larger bolt. The Mark 12’s bolt (top) dwarfs that of a 5.56 AR’s.


The folding front and rear sights are both from Midwest Industries. The flash suppressor is DPMS’s design.

At 18 inches, the barrel is a nice compromise. Yes, shorter would be handier, but you’d have velocity loss and muzzle-blast issues. At 20 inches and longer, it might make the rifle just a tad too long. The twist is fast enough to stabilize any bullet you’re going to be using in a magazine-fed .308 rifle.

The bolt and carrier are a very interesting combo. Made of 8620 steel, they are heat-treated and Parkerized as per mil-spec, and the carrier is clearly a .308 part. The front half is large enough to handle the .308-proportioned bolt, and the rear is small enough to fit into the AR-15 dimensioned buffer tube. On that buffer tube is a Magpul CTR stock. If you wanted a different stock, you could swap the Magpul out for some other brand that fits mil-spec-diameter buffer tubes.

The longer and heavier .308 carrier is driven by an AR-15 buffer spring and a shortened CAR-type AR buffer weight. To work the bolt, the Mark 12 has a charging handle that is longer than that of a standard AR (obviously) but otherwise works in identical fashion.

The fluted barrel ends in a flash hider, one designed by DPMS for effective function and made for .308 use.

As far as handling and cleaning, the Mark 12 is so utterly and exactly like your bog-standard AR-15 in those regards that anyone who feels the need to explain it you must have assumed you slept through that class. But there’s one exception: The trigger guard is not hinged for wintertime use. Otherwise, it is all the same, albeit some of the parts are bigger.

The best aspect for you, the prospective buyer and shooter of the DPMS Mark 12, are the magazines. You see, in the .308 Stoner-system world, there is a near-religious fault line: What magazine do you use? I know of rifles in this class that use metric FAL magazines; G3 magazines; slightly and heavily modified M14 magazines; and the ones the Armalite-brand rifles now use, an extensively modified M14 design that is newly made.

What does the DPMS use? The original 1950s-era AR-10 “waffle” magazine type. No, you don’t have to invest in collector’s magazines from that era, as the magazines are now newly made from several sources since the government has been buying them for use in the SR-25/M110 rifle.

Also, you can buy brand-new polymer magazines for the Mark 12 from Magpul, and POF-USA makes a 25-r
ound magazine as well. You can stuff your load-bearing vest as full as you want (or can stand up wearing) with 7.62×51 bargain magazines and not bust the bank by buying Dutch-marked 1950s magazines at $200 each.

I shot the Mark 12 with all the mags I had: the DPMS magazines, the Magpul and the POF-USA (I have no 1950s-era magazines to put to the test, alas), and it worked flawlessly.

At a smidgen over 91⁄2 pounds bare, the recoil on the Mark 12 is not going to muss your hair. On this subject, our aspirations are always going to collide with vigor against our abilities. Yes, I’d much rather carry a 71⁄2-pound rifle than one that starts out two pounds heavier than that. But shooting the lighter rifle is not going to be fun at all.


Accuracy Results | DPMS MARK 12
7.62×51/.308 Winchester Bullet Weight (gr.) Muzzle Velocity (fps) Standard Deviation Avg. Group (in.)
DAG93 FMJ 150 2,615 16.4 2.00
Hornady TAP 110 2,944 31.4 2.00
Hornady TAP 155 2,563 12.9 1.50
Hornady Match 155 2,649 8.7 1.25
Remington Swift 165 2,507 13.1 1.75
Federal Gold Match OTM 168 2,499 9.3 1.25
DAG93 is German surplus ammo. Accuracy results are averages of four five-shot groups fired at 100 yards off a sandbagrest. Velocities are averages of five shots fired measured on a CED M2 chronograph, 18-inch spacing, 15 feet from the muzzle. Abbreviation:FMJ, full metal jacket; OTM, open tip match.


The Mark 12 receiver features a more sculpted look and sports a spring-loaded dust cover and forward assist.

“In real life you’ll never notice the recoil!” the gun-shop commandos will exclaim, and they may be right. You may not notice it, but it will still have a deleterious effect on your shooting. Better to lay off the super-size fries, get a little more time on the treadmill and pack the heavier rifle. That’s especially wise if you feel a combat rifle is not fully capable unless you’ve bolted on a light, scope, laser and vertical fore-grip. All those will add weight, and you could easily (if you didn’t restrain yourself) end up with as rifle closer to 12 pounds than nine.

While the recoil isn’t a big deal, it is still more than what you’ll experience with a 5.56 rifle. Unlike a hot load in a lightweight 5.56, the Mark 12 recoil is a pushy kind of thing instead of snappily coming back to you.

The two-stage trigger DPMS installed in the Mark 12 made shooting not a big deal at all, and the top rail, since it is a standard Picatinny rail, made clamping a scope on the rifle a piece of cake. I affixed my all-purpose Leupold 3-9X in LaRue mount. As expected, it nestled over the military-issue A2 rear sight without a problem and provided enough eye relief to avoid having my forehead dinged under .308 recoil.

Still, 200 rounds of benchrest shooting does take a toll in felt recoil, and I was happy to take a break before shooting drills. For work inside of 25 yards I figured 3X was a bit more magnification than I needed, so I took off the Leupold and swapped it for an EOTech XPS3. The dot-in-circle reticle of the EOTech made fast shooting at CQB distances easy and fun.

On the close-range work, I found it easy to use the “pushy” recoil of the Mark 12 to my advantage; I simply let the rifle do what it was going to do, and while that was going on, I simply transitioned to the next target. By the time I was there, the rifle was ready to go. Rather than fight it, I floated it.

The excellent ergonomics of the AR system help, and the balance of the Mark 12 is also good. In my hands it has a slightly forward balance–not neutral but not as front-heavy as, say, a FAL.

If you find 7.62×51 recoil to be a bit much, you can switch to Hornady TAP ammo for defensive work. This 110-grain load is quite soft in recoil, and if that proves to be too much you really have to step back to the 5.56.

Now, you may well ask, “What is this for?” I can see a number of uses, and not all in the defensive arena. If you want an accurate, reliable hunting rifle where semiautos are legal, and you favor the .308 as your deer-shooting caliber, then the Mark 12 will serve nicely. Simply block the magazine you use to whatever your state regs require, and get to it.

In a defensive use, the big bonus of the .308 is penetration. While 5.56 ammo requires special bullets and a bit of luck to penetrate into a vehicle, the .308 will do it nicely with plain old ball ammo. If your job or situation may call for dealing with vehicular-based miscreants, you’ll be set.

As a sniper rifle, the Mark 12 has
a lot to recommend itself. Again, the weight won’t be a problem, and the accuracy is certainly a plus. The less than full-length barrel is a hindrance to full velocity, but the gain in speed is not worth the extra size you’d have to put up with, at least not in my opinion.

While a bolt gun is going to do better past 600 yards, inside of that the fast follow-up shots the self-loading Mark 12 offers is all to the good. One of the reasons the military is looking into semiauto sniper rifles is because our troops overseas found that when they had a target, they often had many of them. The situation was not the classic “one shot at 1,000 yards” but rather shoot the one bad guy you see and find that 100 of his friends want to know just what happened to him.

Reloaders will be happy; the Mark 12 treats the brass with care. Oh, you’ll know it came out of a self-loading rifle, but it hasn’t been creased or nearly bent in half, as some designs will do. The brass is not flung into the next zip code either. Cleaning concerns are the same as they are for any other direct-impingement AR.

If you want a 7.62×51-chambered, self-loading rifle, you really ought to be looking at DPMS.


Because the Mark 12 employs a mil-spec buffer tube, it will take any stock designed for that specification. The rifle comes with a Magpul CTR.

  • Mike

    Bought one of these and had failure to feed and eject every other shot. This company needs to re work this gun before they sell any more. Tried to contact the company and never heard back…. Be careful.

    • Devil Dog

      I had the same problem with mine and sent it back in to DPMS. They replaced the Bolt/Bolt Carrier and were able to get it worked out. I have had no problems since I got it back, and with some of my custom reloads am shooting sub MOA groups. (4" group at 600 yards, 1" at 200 yards). It's frustrating spending this much on a rifle to have these kinds of problems, I'd keep working with DPMS to get it worked out.

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