Maxim Defense MD-11

Maxim Defense MD-11

By: Guy Coursey

The pinnacle of SR-25 performance?


We are now over 20 years removed from the start of the Global War On Terror, aka the “GWOT.” For those who would wax nostalgic over the campaigns in Iraq, Afghanistan, and other garden spots that defined that part of our military history, they will likely remember the progression of infantry weapons that served our armed forces, particularly special operators. Among these was the Knights Armament SR-25, a derivative of Eugene Stoner’s famous AR-10 battle rifle, essentially a larger version of the AR-15 in 7.62×51 NATO. With a higher magazine capacity and faster engagement capability than bolt action rifles, the SR-25 was designed as a Designated Marksman Rifle (DMR). Generally equipped with a low power variable optic (LPVO), DMRs are meant to give specially-trained operators the capability to support small unit maneuver by bringing accurate fire on bad guys at ranges beyond the standard infantry weapons, but not quite as far or as accurate as a sniper. Though the SR-25 was phased out of use by SOCOM by 2017, its legacy and many variations endure in the civilian market. One of the latest and most refined versions is the Maxim Defense MD-11 SR-25. Debuting at SHOT Show in 2022, the MD-11 may represent the pinnacle of the SR-25 line in both form and function.

Checking the carbon barrel box rather than 416R stainless, your MD-11 will come equipped with an 18-inch, 1:10 twist Proof Research barrel, which combines an inner core of stainless steel with an outer carbon fiber shell. Benefits of the carbon option? They’re significantly lighter and stiffer, have reduced harmonic vibration, and increased heat dissipation for less POI shift during high rates of fire. The barrel is shrouded by a 15.50” M-LOK cut handguard.

While best known for smaller AR-type carbines, SBRs, and suppressors, Maxim Defense Industries decided an SR-25 built from the ground up with everything the user could possibly want out of the box would be another feather in their cap. The result is the MD-11. The MD-11 uses a traditional direct-impingement gas system and comes in .308 Winchester and 6.5 Creedmoor. It is built on a billet 7075-T6 receiver set, AR-10 style BCG, and an octagonal aluminum forearm with a full-length Picatinny rail on top and M-LOK rails along the sides and bottom. The charging handle is ambidextrous, as is the safety. Furniture consists of a B5 Systems Enhanced SOPMOD buttstock riding on a carbine buffer system, and a BCM Mod 0 handgrip. The muzzle device is a standard military-style A2 birdcage flash hider, which, given the quality of everything else on the MD-11, seems a bit pedestrian, but it works fine. Of significance, the trigger is a two-stage Gisselle SSA-E model, generally accepted as one of the best, with the final stage on mine breaking at about 1.2 pounds. The MD-11 itself weighs in at a light 9 pounds empty and comes with one Lancer L7AWM 20-round magazine, a gun lock, and the usual literature.

The MD-11 is built on the SR-25 platform, with receiver sets carved from 7075-T6 aluminum and coated in either urban grey, arid, or the black shown here. Controls — including the mag release, bolt release, safety selector, and charging handle — are all ambidextrous. The outstanding Geissele SSA-E two-stage trigger is standard equipment. The MD-11 ships with one Lacer L7AWM 20-round magazine.

The heart of the MD-11 is not its receiver or bolt carrier group but rather its barrel. The MD-11 can be purchased with either an 18-inch, 1:10 twist, 416R stainless steel or a carbon fiber barrel from Proof Research, a manufacturer of next-generation barrels that use aerospace materials and ultra-modern manufacturing processes. My copy came with the carbon fiber variant, so we will focus on that here. Proof carbon-fiber barrels have a core of 416R stainless steel wrapped with carbon fiber. This produces a barrel that is significantly lighter than a similar profile steel barrel but also increases stiffness, reduces harmonic vibration, and dissipates heat much more quickly. The result is match-grade accuracy, durability, and minimal POI shift during high rates of fire. Such barrels do not come cheap and are a big reason for a price tag that is close to four grand for the MD-11 equipped as such. But you get what you pay for, and the cool factor is near the top of the scale.

The MD-11’s direct-impingement operating system uses a robust SR-25 spec bolt-carrier group. An oversized and ambi Radian Raptor-LT charging handle is factory equipment.

At SHOT Show Range Day, average humans were dinging steel at well over 800 yards from

Bringing up the rear is a B5 Systems Enhanced SOPMOD buttstock — featuring built-in storage, a sloped cheekpiece, and ambi QD sling swivel cups — riding on a fluted buffer tube holding a carbine-length buffer system. A Bravo Company Mod 0 pistol grip provides some of the best all-weather texturing in the business and also features built-in storage.

the bench with the MD-11, so my expectations were high as I went to the range. They were even higher when my copy came equipped with a Trijicon Tenmile 4.5-30×56 34mm scope in a Larue QD mount. Featuring a red/green MOA precision tree, elevation adjuster, and return to zero feature, I could not have hoped for much better than the Tenmile where potential precision was concerned. I will say that any weight savings I may have enjoyed with the MD-11 was offset by this scope/mount combination, however. No matter. Starting at 50 yards from a bench rest using less-expensive Brazilian 147gr CBC ball to get on paper, I moved to 100 yards, firing five-shot groups from loads by PMC, Winchester, Hornady, and Federal. I will freely admit to not being the world’s best precision rifle shooter. However, I believe that the MD-11 can easily achieve sub-MOA accuracy with a better driver. My best groups were turned in using Federal 168gr BTHP Gold Medal Match, with the best at 1” center to center and the next at 1.1 inches. The third group had a knot of four hits just left of dead center that measured 1/2 inch, but was spoiled by a rather disgusting shank with the fifth shot two inches out at 10 o’clock. The MD-11 ate everything I fed it from both the Lancer and a Magpul 20-round PMAG magazine. Recoil was more than manageable, and ejection positive. Very satisfactory.

Durable, precise, and crystal clear, the Tenmile 4.5-30×56 is fast becoming a staff favorite for mid to long-range precision rifle engagements. Between the large 34mm tube and 56mm objective, light transmission is outstanding. Custom-built turrets are available, as are either an MOA or MRAD reticle mounted in either the FFP or SFP. Check out the details at
Making loud things quiet is also a Maxim Defense specialty, and during testing, we had the opportunity to muffle the MD-11 with the company’s impressive DSX-D 7.62mm suppressor. Made from a combination of Titanium and stainless steel, the DSX-D is not only an extremely competent sound and recoil killer but also exceedingly durable. From the factory, the MD-11 is equipped with a standard A2 birdcage flash hider, which — given the other high-end components on this rifle — we thought to be a bit pedestrian.

Another line of products that Maxim Defense is well known for are its top-tier suppressors, and during the course of testing the MD-11, we had the opportunity to take the company’s DSX-D suppressor out for a spin. Takeaways? This is a seriously robust, overbuilt can with impressive sound and recoil-reduction performance and minimal gas blowback for a non-flow-through design. Made from a combination of Titanium and stainless steel and available in either 5.56 or 7.62mm variants, its simple three-piece design is user-serviceable and can be disassembled with common hand tools for routine cleaning. We’re looking forward to putting more time behind this one.


The author freely admits that precision rifle work is not his specialty, but regardless, the MD-11 showed half-MOA capability on the lower-right target, only to be ruined by one errant shot. Otherwise, one-MOA five-shot groups came with relative ease using 168-gr. Federal Gold Medal Match.

In conclusion, the Maxim MD-11 represents one of the highest forms of the SR-25 platform, which should continue to be popular for a long time to come. While certainly not the cheapest option out there, the MD-11 is of exceptional quality and can fulfill the requirements of a DMR and a precision rifle with the right ammo, scope, and operator. Check out the MD-11 at your nearest dealer, or for more information, contact Maxim Defense; Tel.: (239) 580-7800; E-mail: [email protected]; Web:


Action:                        Semi-Auto DI

Caliber:                      .308 Win.

Barrel:                       18” Carbon Fiber Wrapped

Weight:                      9 lbs.

Sights:                      Picatinny rail

Capacity:                   20

MSRP:                       $3,595 to $3,995

The MD-11, with its low-recoil characteristics (especially suppressed), its Geissele SSA-E two-stage trigger, and the downrange-precision capability afforded by the carbon-wrapped Proof Research barrel, gives you all of the advantages you need to ring far-off steel. Our final conclusion? You truly do get what you pay for with the MD-11.