The DARPA XM-3

By Steve Reichert

The original article was published by Soldier of Fortune in the summer of 2012. It has since been updated below

For years Marine snipers have been using their coveted bolt-action M40s (A1/2/3/5) to take out enemies all over the world. These rifles are all built by hand at the Marine Corps Precision Weapons Shop (PWS) in Quantico, VA. The Marines at PWS build some of the most accurate sniper rifles in DOD, yet when 9/11 sent the Marines into Iraq and Afghanistan the shortcomings of the new M40A3 were soon apparent. Marines on the front lines needed rifles that were shorter and lighter, had better fields of view, and were quiet. But the weapons procurement timelines in non-special operational forces are long, and what should take months typically takes years. This is where the DARPA XM-3 came in

Enemy Snipers Take a Toll

When urgent needs statements (UNSs) started coming from the sniper platoons on the front lines, one government agency was quick to respond—the Defense Advanced Research Project Agency, better known as DARPA. In 2003 DARPA became interested in helping the Marine snipers counter insurgent snipers who had been successful in spotting and killing Marine snipers in hide sites. When our nation’s elite snipers are killed by enemy snipers, it tends to get the attention of all groups in DOD, DARPA being no exception.

DARPA looked at the problem from a technology standpoint. What could DARPA do to increase the Marine snipers’ chances of survival while improving their lethality? One project they were working on was a sniper detection system called the Boomerang. In 2004, as this system was being field tested at Camp Lejeune against Marine snipers on Hathcock Range, the Marine Corps’ representative to DARPA, Col Otto Weigl, was on deck watching the Marine snipers fire against the system. The Col noticed an older gentleman getting down in the dirt and talking to the Marines behind the rifles. The man asking the questions was LtCol Norm Chandler USMC (Ret.). He had been responsible for building Hathcock range in the 90s, so he took an interest any time a new technology was tested there. LtCol Chandler had noticed a Marine was having issues with his optics, and he asked what issues they were having in general with their currently issued M40A3s. That day on the range Col Weigl learned about the shortcomings of the Marines’ sniper rifles and equipment.

DARPA gets in bed

I was the SNCOIC of the 2nd Marine Division’s Pre-Sniper course in 2004 when I got a call from LtCol Chandler. I had known him for years and knew his company built some rock-solid rifles. LtCol Chandler told me he had spoken extensively with Col Weigl and that the Col might be able to provide some technological assistance for the next set of units heading out the door. I found it hard to believe that an O-6 would have taken such an interest so I called Col Weigl’s office at the Pentagon. The Col explained what DARPA could and couldn’t do, and asked to arrange a meeting with snipers and some key leadership within the Division. That year DARPA held a small conference with Marine snipers to gather information on equipment and desired improvements. To develop a new program, DARPA decided to do an evaluation of off-the-shelf equipment that could be acquired, deployed, and evaluated.

The conference and evaluation led to many developments. “In mid-2005,” Col Weigl recounts, “DARPA provided a deploying MEU with spotting scopes, laser range finders, clip on night-vision devices for weapons, carbine suppressors and deployed 2 Mirage 1200 counter sniper systems. DARPA also provided night vision and suppressors to the Marine Corps Warfighting Lab’s first distributed operations platoon deployed in Afghanistan.”

The initial equipment DARPA fielded was used in combat on a daily basis. The technical reports and after-action reports provided DARPA with the justification needed to start the M40XM program. Since DARPA had used Iron Brigade Armory to get the equipment to the Marines, they had a great working relationship. The folks at DARPA also understood what a battle-hardened rifle needed, so it was a natural fit for them to select Iron Brigade Armory. In 2005 DARPA contracted IBA to build and test lightweight sniper rifles that incorporated the improvements the snipers desired in combat.

DARPA’s mission was to develop a complete sniper system for both day and night operations. The system had to be lighter and smaller than the existing M40s while having better accuracy, clip-on night vision that did not require a re-zero, better optics, and better stock, and it had to be suppressed.

Getting funding for the project was not an issue. According to Col Weigl, “Funding for the prototypes XM1 through XM3, as well as the 56 full systems was not a problem since there was interest from the DARPA director Tony Tether, SOCOM General Brown, and USMC General Mattis.” The support and funding made it possible to expedite the development and fielding of the systems.

One of only two XM-3’s with a Rikert Engineering take-down stock, on an OP in Ramadi Iraq

Developing the M40XM

IBA began development of the M40XM1 in early 2005. From the outset they wanted to develop a rifle that was lighter and shorter and that possessed a suppressor and night vision capability. Some of the issues with the Army’s M24 and the Marines’ M40A3s were long barrels, long actions (M24), weaver rails (M24), heavy stocks (M40A3), and fixed power optics. IBA had to look at each issue on the M24 and M40A3 with a critical eye. DARPA wasn’t interested in developing another M40A3 boat anchor. IBA looked at all the parts in a standard Remington 700 action and began working to lighten and modify any factory parts to achieve better results.

So what made the XM3 so different? Here are some of the main elements that set them apart:

The receivers were clip slotted to accept the reverse-engineered titianium picatinny rail (IBA Design) to fit firmly.

The receivers’ internal threads were opened up to 1.070” to allow a perfectly true alignment with the bolt face and chamber/bore dimension. The chamber was cut to accept M118LR ammo.

The titanium recoil lug was built with the 1.070” diameter opening for the larger-barrel threads and surface ground true.

The stainless steel magazine box was hand fitted and welded to eliminate movement when assembled.

The stocks were custom made for the project.

The barreled actions were bedded in titanium Devcon and Marine Tex to allow for decades of hard use without losing torque or consistency.

Nightforce made a full 1 MOA elevation adjustment on their NXS 3.5-15X50’s to allow for faster dope changes at distance. These scopes had 1/4 MOA windage.

During the development, IBA went through a total of five configurations before settling on the XM3’s final configuration. The first and most obvious departure from a regular M40A3 was the stock. The Marines who used the M40A1 loved the sleek, low-profile stock. It didn’t weigh much, it was easy to maneuver, and it fit most guys well. The main downside to the McMillian A1 stock was the low comb height—plus the fact that the forend was not wide enough to accept the new in-line night vision mounts. I called McMillian Brothers in Arizona and spoke to Mr. McMillian himself. I explained what the XM program was about and asked if he could take an A1 rear, raise the comb half an inch, and use an A3 forend. He said it wouldn’t be a problem, and they got on it. Within three weeks I had the new A6 (as it was called at the time—it’s now the A1-3) stock at my doorstep. Now the stock problem was solved! IBA bedded the the new A6 onto my existing Chandler rifle and we began putting it through it’s paces. Within a month I had sent the stock to Rikert Engineering in MA to have it modified into a take-down stock. This same stock would eventually end up overseas on a Marine Corps XM-3.

DARPA XM-3 out with one of the MEU’s

The other major departures from the sniper rifles of the day were in barrel length and contour. The barrel had to be short enough to allow maneuverability yet long enough to deliver a 10” group at 1,000 yards. If the barrel was too heavy, maneuverability would decrease, yet if the barrel was too light it would only be able to shoot a few rounds before the groups started to shift due to barrel temperature. IBA tested a number of barrel lengths, ranging from 16 to 20 inches and in different contours and even a fluted version. Each rifle with a different length was assigned an XM designator starting with XM1 through XM3. In each case, everything on the prototype rifles was kept the same except the barrel. During the final phases of testing it was found that the 18” barrels had no issues keeping up with their longer 20” brethren. The final barrel length was set at 18.5”, and the contour was a modified #7. The straight taper on the barrel was only 2” vs. 4” and the overall diameter at the muzzle was .85” vs. .980”. This helped reduce a lot of the rifle’s weight while not negatively affecting accuracy or effective range. A number of the groups at 1,000 yards were -1 MOA.

Once the final rifle configuration had been settled on, the prototype XM3 was sent to the Naval Surface Warfare Center in Crane, Indiana for testing, safety certification, and a comparison test. The tests conducted at Crane were very scientific. Every round was fired on a fully instrumented range and recorded. The XM3 was tested side by side with the Mk13 Mod 5 and the Mk 11 Mod 0. The XM3 did extremely well during testing.

The time it took IBA to develop and field the XM3 rifle was light years ahead of typical government programs. By the time the first XM3 rifle had been shipped out the door, only 12 months had passed since DARPA had contacted them.

The DARPA XM3 rolls out

You would think with such support the Marines would be chomping at the bit to get these new weapons systems in hand. Despite the interest from Gen Mattis, some Marine program managers at Marine Corps Systems Command (SYSCOM) said there were no requirements for a new sniper rifle and made DARPA jump through numerous hoops. The Marines tested and evaluated the XM3 in Quantico. SYSCOM required an official safety certification from the Navy’s Surface Warfare Center, and once the bureaucratic pushback from SYSCOM, PWS, and unit armory and supply officers was overcome, the systems were sent to the units. In 2006 the Marine Corps started to take delivery of the XM3 sniper weapon system. The system included:

Rifle – XM3

Hardigg iM3200 Storm Case

Suppressor – Surefire FA762SS w/ soft case

Day Scope – Nightforce NXS 3.5-15X50 MD w/ ZS 1 MOA Elv & 1/4 MOA Wind

Night Vision Unit – AN/PVS-22 UNS w/ soft case

Harris Bipod – BRMS w/ PodLoc

Eagle Cheekpiece

Turner Saddlery AWS Sling

Dewey Cleaning Rod and Bore Guide

Seekonk Torque Wrench @ 68 in lb.

Kleinendorst Bolt Disassembly Tool

Allen 5/32 T-Wrench

SK T30 T-Wrench

Kobalt ½” Adapter

3 Bore Brushes

A number of the first units to receive the XM3 were West Coast infantry battalions. Col Weigl had been working with GySgt Ken Sutherby, one of the Corps’ top snipers, to ensure the rifles made a smooth transition into the fleet. GySgt Sutherby was instrumental in ensuring that the sniper platoons who received the XM3s knew how they operated and what they could and could not do. This was the first time the Marines had seen in-line night vision devices that did not require them to be zeroed to a specific rifle. It was also the first time the Marines had variable power scopes and most importantly the first time they were able to shoot their rifles suppressed.

Col Weigl and Norm Chandler, Jr. were on hand at Camp Pendleton when the first shipment of rifles was delivered to I-MEF. As with all IBA rifles the XM3s were test fired and zeroed before leaving the shop. When the Marines cracked open the cases and went to zero the rifles, they were pleasantly surprised that all the rifles were within a ½ MOA of their point of aim. The Marines were able to hit their targets all the way out to 1,000 yards with ease. But that night was when the Marines’ jaws really dropped. After the sun went down, the Marines tossed on the PVS-26 universal Night Sights. Using their prior data, more than 75% of the Marines had first-round hits at 900 yards, fully suppressed!

One of only two DARPA XM3’s with fluted barrels and take-down stocks

The Marines loved the fact that the rifle was more compact and lighter and had more capabilities than their existing M40A3s. The rifle was mostly able to keep up accuracy-wise with the longer-barreled M40A3s. Even though the barrel on the XM3 was a full six inches shorter, muzzle velocity was only reduced by 100fps on average. Did this make the rifle less accurate? No. It just meant that, depending on the environment, the rounds sometimes went trans-sonic prior to reaching the 1,000-yard mark.

DARPA XM3 Goes to War

Shortly after I-MEF took receipt of the XM-3s, the first units in II-MEF took receipt of theirs and two additional XM-3’s were built for MCWL (Marine Corps Warfighting Laboratory). The two MCWL XM-3’s had a special low-profile take-down feature built into them. One of these stocks came off my personal Chandler rifle. By mid 2006 there were dozens of XM3s in Iraq quietly killing insurgents. One of the first reports back described a team of three insurgents emplacing an IED about 400 yards away from the team. It was just after midnight when the team shot the first insurgent. The other two had no idea where the shot came from and starting running directly towards the team. The sniper took out the second guy, while the third guy kept running towards the team. The third guy was dropped about 200 yards from the team’s position. There were reports like this coming back from theater monthly.

I thought the Marines themselves could best sum up their thoughts on the XM3:

“I last deployed in 2008 and carried the XM-3 on every operation. The rifle shot great and the size was perfect for the insert platforms.” GySgt USMC (MARSOC)

“I think the move to the XM-3 was great—beautiful gun, big step forward. Never had any problem with function (or malfunction)—awesome rifle, love it.” MGySgt USMC (2nd Force Recon)

“The length of the XM-3 helped with employment issues as well. In an urban environment where you can get some standoff from your loophole, size is not such an issue. In the mountains of Afghanistan and in the small mud buildings of our AO, we were often wedged into our positions. A shorter weapon was welcomed.” Sgt USMC (Sniper Instructor)

“Why we haven’t adopted this model of rifle I have no idea. I love this rifle. If I could afford it, I would buy one myself.” SSgt USMC (Sniper Instructor)

“The greatest advantage to this rifle compared to the M40A3 was the decreased weight, suppressor, inline night sight rail over the barrel, and variable power scope. That would not be significant nowadays, but back then, it was a force multiplier.” CWO2 USMC (Marine Gunner & former Sniper School SNCOIC)

“The length of the rifle was its real advantage. To be able to T-bone it across your pack and not have it sticking as far out as our 40s was advantageous” SSgt USMC (Sniper School Instructor)

“Everyone in our platoon loved that gun. Nobody ever got to take it out with them because Gunny was so possessive of it. He called it “his gun.” Sgt USMC (Sniper School Instructor)

“At the time, none of our 40s were set up with suppressors. That in my opinion is what gave it the advantage over the M40s” GySgt USMC (Sniper School Instructor)

“I personally shot over 1,000 rounds through the XM-3 and had no issues. With M118 I held sub minute of angle groups back to the 1,000-yard line suppressed and non-suppressed. This was the norm and not the anomaly.” CWO2 USMC (Marine Gunner & former Sniper School SNCOIC)

“These benefits are hard to explain to a commander that only leaves the wire under the protection of an armored vehicle. We tried one night, but our Battalion Commander could not see how any military unit could justify spending that much money on a weapon system. We explained to him that a lot of our heavy weapons cost a lot more. This was to no avail. In the end, I left him with a playing card that I had shot the spade out of from 100 yards using the XM-3.” Sgt USMC (Sniper Instructor)

“All XM-3 rifles (I mean every one) that I tested were sub-minute of angle guns at 300 yards with Black Hills ammunition and I never encountered any stoppages, malfunctions or failures to fire during any tests or field use.” MGySgt USMC (Former Marine Rifle Team SNCOIC)

“All around, the XM3 was the solution for a primarily urban fight and the required long-range shooting when the opportunity presented itself. The suppressed capabilities allow snipers to remain uncompromised and take more than one shot from a concealed position.” GySgt USMC (Sniper School Instructor)