How the U.S. Army Builds the M14 EBR-RI

June 21, 2018 By Eric R. Poole

We met Doug Carlstrom inside a simple reinforced structure reminiscent of the Cold War. It's subtly located in a corner of the 946-acre island within the historic gates of Rock Island Arsenal. A career U.S. Army veteran with experience brought back from the Vietnam War, Carlstrom has witnessed the military trials of nearly all modern infantry small arms spanning the adoption of the M9 and M11 pistols to more recent variants of the M16. In 2011 Carlstrom and his five-man team were continuing their service as civilian contractors to TACOM, leading the development, testing and issue of the M14 EBR-RI.

M14-EBR-RI-Box — During trips to Iraq and Afghanistan, Doug Carlstrom of TACOM observed soldiers trying to adapt rack-grade M14s and M21s with commercial mounts, rings and optics.

"I was deployed to Iraq in 2004 and to Afghanistan in 2006 to open a small arms support center," Carlstrom says. "I opened Camp Anaconda in Balad, Iraq, and started learning how soldiers were using their rifles. At that time, units were pulling M14s out of storage and issuing them to marksmen within a squad for more accuracy, range and effectiveness."

The first M14 rifles were fielded to units as they came out of Anniston Army Depot. Those M14s were still wearing wooden or nylon stocks and a brown nylon handguard. They were equipped with only one magazine and had no provisions for optics. Carlstrom observed soldiers trying to attach commercial mounts, rings and optics to these M14s with little consistency or repeatable accuracy. After seeing soldiers trying to adapt the M14 to a modern battlefield, Carlstrom concluded that this situation was unacceptable. When he returned to CONUS, he set out to resolve this problem.

M14-EBR-RI-Beginning — During trips to Iraq and Afghanistan, Doug Carlstrom of TACOM observed soldiers trying to adapt rack-grade M14s and M21s with commercial mounts, rings and optics.

THE TRANSFORMATION

All of the joint services were using some configuration of the M14 EBR. The M14 EBR-RI was built and tested at Rock Island Arsenal by the team that developed it. It was a response to the large number of Operational Need Statements (ONS) submitted for M14 rifles to support the role of a Squad Designated Marksman (SDM). The M14 EBR-RI was designed to standardize the optic among soldiers, offers sustainability in the field and featured a chassis constructed from lightweight aircraft aluminum capable of supporting the use of a night vision device in front of the day optic. It also needed to support the use of various combat-related accessories never seen before this age of warfare. It had to be an out-of-the-box system, so when any soldier opened his package, inside he would find:

1 M14 EBR-RI rifle

1 Leupold Mark 4 LR/T
3.5-10x40mm scope assembly

6 Magazines, 20 rounds

1 Sling

1 Otis 7.62 cleaning kit

The Rock Island team unpacked the rifles from their cardboard shipping boxes, then removed a wooden or nylon stock, plastic handguard, op rod guide block and barrelband. The only major subassembly that remained was the barreled action. "We disassemble and use all but five parts," said Carlstrom. "They are very good, MIL-SPEC components. Since the program started, we've only encountered one shot-out barrel on an overhauled receiver."

Moving past pallets and parts bins of leftover components, the rifle advanced to an efficient operation that transformed an M14 into an M14 EBR-RI in less than 20 minutes. A pile of EBR aluminum chassis systems from Sage International (sageinternationalltd.com) were piled on a bench, and a builder picked one at random for disassembly. He had to remove the top cover and extract the new guide rod block that's largely responsible for the improved accuracy. The shim kits supplied by Sage were difficult to work with, so TACOM conferred with Sage to develop a washer that met all of the tolerance stack-ups they needed in a replacement crush washer.

newest-Sage-International-EBR — The newest Sage International EBR chassis carries an ERGO pistol grip. The stock can be collapsed while shouldered without injury to the shooting hand. A bullet tip can be used to depress a small detent and adjust the comb height.

At another station, another veteran, Dan, pulled a long black box containing a Leupold Mark 4 LR/T 3.5-10x40mm scope from a wall of identical boxes stacked seven feet high. Just one man was responsible for placing this scope in a set of Leupold Mark 4 medium-height tactical rings. He then aligned the crosshairs once the rings were mounted to a six-inch Picatinny rail section. The rail section was permanently affixed to an eight-inch square sheet of stainless steel, which was secured in a vice that was used for nothing else. Peering through the scope as he tightened the screws of the ring cap in a cross pattern, Dan watched to make sure the mil-dot reticle remained perfectly square with a grid he had posted on a wall 10 yards away. He then went on to boresight the optic before removing it from its fixture and placing it back into the box.

With the EBR chassis resting in a wooden fixture, an EBR builder picked an operating rod, guide rod and spring assembly from parts bins just a few feet away. He started to build up the barreled action and checked for function before moving on to the next step. It was important to the builder that he verified that the unique Sage op rod guide was properly positioned on the barreled action. The red dot should face the muzzle when installed correctly. He then charged the operating rod to the rear a few times to ensure that the rod wasn't binding with the operating rod guide in any way.

The builder then placed the barreled action into the tight-fitting aluminum chassis. It usually required some type of encouragement from a small mallet with a replaceable nylon head. When the action was seated into the chassis, he rolled the rifle over and inserted a trigger assembly that he obtained from another nearby parts bin.

With the action seated front and rear, he visually checked for the alignment of the chassis' holes to ensure proper alignment of the coarse-thread screws that wear red Loctite on the threads. The fore-end of the chassis was now secured to the operating rod guide at three points, which would effectively free-float the barrel ahead of this guide. At that point, the top cover with integral rail assembly was reinstalled using six 5/32-inch Allen-head screws, a barrel whip control screw was brought down through the top cover until it just barely touched the top of the barrel and a jam screw was run into the side and interrupted the threads. This feature of the Sage International chassis system had shown itself to stop barrel whip. A key point was that no pressure is put on the barrel.

A special stainless-steel washer slid over the barrel to properly aid in the piston assembly's function. A new piston assembly then slid over the barrel and was screwed on with a special wrench that helped align the gas system. The M14's legendary gas system was completed when the builder screwed on the gas cylinder plug.

After sliding the front sight assembly across the dovetail of the flash suppressor assembly, the builder tightened it with a pair of pliers designed specifically for the M14 castle nut. Before reaching this stage in the build process, however, the flash hider has had the bore size increased. The standard muzzle device was opened up with a #7 tapered reamer, which helped to prevent a phenomenon called water-drop deflection at the muzzle.

With the stock installed, the builder worked on securing a solid platform for the Leupold sighting system. He attached a cantilever base to the cartridge clip guide and secured the Sage International cantilever base to the chassis' top rail with the help of two tensioning throw levers. Though the cantilever base could be removed, it should've only be done in the event that the primary optic failed during battle. You could remove the scope and cantilever mount if the warfighter needed to use the iron sights. Removing the optic by removing the cantilever base demonstrated that a soldier could expect the same zero repeatability and zero retention within one MOA if it needed to be rolled off the rifle. With the cantilever rail removed, the SDM was free to use the M14's iron sights as a backup sighting system. Even when using just the iron sights, SDMs have been reported to have successfully engaged and defeated targets out to 600 yards.

ACCURACY CHECK

Once the Rock Island team completed a build, each new M14 EBR-RI rifle was placed on a table outside the facility's 100-yard indoor test range to be function fired and checked for TACOM accuracy standards. Each rifle was shot to verify grouping and accuracy, and that target was included with the Leupold box and assigned scope.

RI-Indoor-Range — The transformation from M14 to M14 EBR-RI takes just 20 minutes before the rifle moves to the indoor range for testing.

Some end users faced situations where they needed to use M80 ball. The M14 EBR-RI would shoot this type of 7.62 NATO ammunition with two-MOA results (at best) at 100 yards. An SDM using M118LR would cut that group in half.

For accuracy testing, the Rock Island team pulled from an ample supply of M118LR. The recorded accuracy didn't take place until the tester observed that the rifle had begun to "like itself." These rifles quickly developed a specific wear pattern under recoil that allowed the barreled action to properly settle into the aluminum chassis. This was one reason why they highly advised against any operator or second-echelon armorer removing the chassis system from the rifle. Certain rifles settle in right away. At most, EBR testers allowed each rifle eight rounds, with an average of three to four bullets walking before stopping and revealing a group.

Only once has a rifle ever been condemned at accuracy testing. Although TACOM won't accept anything that shoots more than 1½ MOA, the average group measures .97 MOA. During my visit, four rifles were tested and the poorest accuracy was .76 MOA. The best rifle produced an incredible .44 MOA. I couldn't help but let my mind wander and think of the reaction at the range that would be elicited from the soldier in Afghanistan who is ultimately issued this rifle.

M14-EBR-RI-Accuracy — After testing more than 5,000 M14 EBR-RI rifles with M118LR, only one has ever been rejected for failing the accuracy test. Most rifles average sub-MOA groups at 100 yards.

Accuracy testing hasn't been solely limited to the Rock Island indoor range. Carlstrom has had various opportunities to demo the M14 EBR-RI at other bases. Never having shot anything beyond 300 yards before, one of the TACOM team members, Mike Petersen, was allowed to engage iron maidens during a training exercise at Ft. Lewis prior to a unit's deployment. The EBR proved itself well out to 800.

"We don't lock these rifles in machine rests to get this kind of accuracy," Carlstrom said. "We like to consider the human factor. If we can shoot it well, we know the soldier can do even better. We know that we can never out-shoot these guns."

OUT THE DOOR

Once the rifles are tested for accuracy, scopes set in their rings are removed and returned to the Leupold cardboard boxes as the rifles were lined up on another table ready for packaging. The shipping box was formed as an evaluator cut the measured three-shot group from the target and dropped it into the scope's box for verification. The results of that particular test were logged into a database with the rifle's serial number for reference, should the rifle ever return for another overhaul.

M14-EBR-RI-Boxed — Once the rifle has passed final inspection, the Leupold scope is removed with its rings and packaged with accessories such as this multitool before final shipment to the end-user.

To meet the needs of the U.S. Army SDM program, TACOM-RI selected key components to assemble a package that enhanced the stock M14 weapon system and provided standardized optics and rails for mounting lasers, lights and night vision equipment. A special multitool was created for the M14 EBR-RI that featured a half-inch socket for removing the scope from the cantilever base, a carbon reamer for cleaning the gas piston cylinder and various Allen-head wrenches to remove/tighten the number of Allen-head screws through the rifle's chassis.

To that package a Harris bipod, Sage International forward vertical grip, six vintage 20-round magazines, a sling, an Otis 7.62 cleaning kit and a laser filter/anti-reflection device were also included. With the rifle wrapped in VCI protective paper, the box was closed, a label indicating the rifle's accuracy was placed on the outside of its box, and it was added to a stack of rifles already certified on a wooden palette.

MAINTENANCE

The aircraft-aluminum chassis was tight, and the rifle was configured so that the barreled action did not need to be removed from the chassis. Operator disassembly of the M14 EBR-RI was limited to cleaning of the external parts of the stock system, exposed action components and disassembly of the gas system to access the gas piston cylinder assembly. The M14 barreled action and forward rail should not be removed from the stock at the operator level. Any maintenance that required a barreled action to be removed from the stock should've be done by an armorer. Cleaning the gas system was accomplished by the removal of the gas plug nut using a 3/8-inch wrench or the M14 combination tool. Remove the gas piston itself, and remove all carbon buildup. The carbon could be taken out using the reamer on the M14 EBR combo tool. Remove the trigger assembly by pulling out on the triggerguard and rotating it to the outward position. Once the triggerguard has been rotated to this position, pull upward on the assembly and lift to remove it from the stock. It can now be cleaned and lubed. To prevent excessive wear of the stock components, this should not be done for basic preventative maintenance.

CONCLUSION

The M14 EBR-RI was a rack-stock M14 rifle that had been mated to the Sage International EBR aluminum-billet stock system. This stock system in conjunction with the Leupold precision optics and Sage International cantilever mount made the M14 EBR-RI capable of shooting less than one minute of angle in most cases.

TACOM received the call for a "significant quantity" of rifles that could enhance the battlefield effectiveness of a squad designated marksman. This call left the number of rifles that the Army would need delivered open-ended. Most of the fighting that went on overseas was a small arms war, and the retired veterans and contractors that were working at TACOM Rock Island felt very connected to the end user's mission. To date, there is still no doctrine for an SDM rifle. So at least for the near future, the M14 will have a place on the battlefront.

Officials at the Pentagon considered the M14 EBR-RI an interim solution and indicate that the U.S. Army is still looking for a more permanent solution. Until then, Carlstrom's team proudly shows up to work each day to build and test the newest generation of M14s.

"The solution is months and months away," Carlstrom indicates. "But this is a 90 percent solution today. We have had generals and other VIPs in our government inspect and shoot one of these EBRs for themselves. It's a bit of a circus act, but we like to tape a dime to the target when they come to experience it. Twelve out of 18 generals have shot a dime at 100 yards, and they leave impressed."

On the 5th day of May 2011, this team built the 5,000th rifle, one of only two ever inducted into the Rock Island Arsenal Museum the same day it was built (the other being a M1903 Springfield serial number 1). The Rock Island Arsenal Museum is the second-oldest U.S. Army museum, which is open to the public (riamwr.com/museum).