One solution, military planners could see, was employing a more capable cartridge already in the system: the 7.62x51 mm NATO. Today’s standard U.S. sniper cartridge, the 175-grain, M118 Long Range load, delivers four times the foot-pounds of energy as the standard 62-grain, 5.56 mm round at extended ranges. In other words, at 600 meters the 7.62 mm round packs about as much energy—1,000 ft.-lbs.—as the 5.56 mm round at 100 meters.
Although M14 rifles were pulled from depot storage, fitted with scopes, shipped to Afghanistan and issued to Army and Marine designated riflemen, the guns proved less than ideal for today’s warfare. First, their fixed stocks could not be adjusted to fit the length-of-pull needed for today’s body armor. And second, the 40-year-old rifles could not accommodate modern accessories such as lasers, night vision scopes and lights, which require MIL STD 1913 Picatinny rails. Fortunately, a solution had already been developed by the U.S. Navy’s Surface Warfare Center at Crane, Ind.
The SEAL CQB Rifle
One year before the 2001 terrorist attacks, U.S. Navy SEALs had gone to Crane to request an updated version of the 42-year-old M14. Great believers in the M14’s reliability and the 7.62x51 mm NATO cartridge’s lethality, they wanted a shortened version with a pistol grip and adjustable-length buttstock for close-quarters use.
The design task fell to David Armstrong, an accomplished small arms engineer who previously had developed the well-received SOPMOD (Special Operations Peculiar Modification System) for the M4 carbine. A mechanical engineer, machinist and recreational shooter, Armstrong began by searching for an off-the-shelf collapsible buttstock.
After trying several, he chose a Sage Int’l collapsible, pistol-grip stock made for the Remington Model 870 shotgun. The telescoping design offered five lengths of pull, in 1-inch increments, that worked well with body armor. Armstrong connected the Sage buttstock to the forward section of a modified M14 fiberglass stock. He also replaced the rifle’s standard 22-inch barrel with an 18-inch unit, reducing its overall length by nearly 10 inches, to 35 inches.
The fiberglass stock, however, did not satisfy him. “The [M14] design has always been tough to beat for reliability, but required laborsome bedding and tuning for best accuracy,” he explained. Earlier sniper versions of the M14, especially the M21 Sniper System, which used a resin-impregnated stock with epoxy bedding, proved so temperamental that snipers were instructed not to remove the action from the stock while cleaning it.
Armstrong took the bold step of designing his own chassis stock, machined from aircraft-grade aluminum. Not only would this be more rigid than fiberglass, but it would include an aluminum bedding block and an assortment of Picatinny rails for optical and illumination accessories. The result was a true “drop-in” stock, requiring no bedding or special fitting. “This stock floats the gas system through a replacement operating rod guide screwed to the rigid stock fore-end and a simple spacer replacing the front band,” he said. He also modified the Sage buttstock’s cheek rest to give it 2 inches of vertical adjustment in 1/4-inch increments.
In addition to installing quad Picatinny rails around the fore-end, he attached a short-rail scope mount that replaced the M14’s stripper clip guide. The final additions were a more effective flash suppressor, three ambidextrous 1 1/4-inch sling slot locations, and a Harris Engineering S-LM Series S bipod. Patented to the U.S. Navy with Armstrong as its inventor, the chassis stock is now produced under license by Sage Int’l in Oscoda, Mich.