Upgraded Assault Rifles In Store for Commandos.

• Author: Gourley, Scott

U.S. Special Operations Command is already looking to expand the capabilities of its Reduced Signature Assault Rifle--formerly known as the Personal Defense Weapon--before its manufacturer has even delivered the first weapon in the program.

The command is considering the addition of conversion kit options to incorporate 7.62*39 mm caliber ammunition, which is most used in the AK-47 series assault rifle, a "notice of intent" released late January stated.

The original program emerged in March 2017, when the command released an announcement seeking to identify "potential sources within the national technology and industrial base with the ability to provide a conversion kit for the 5.56 mm M4A1 to create a Personal Defense Weapon system."

Kit requirements included conversion to fire the .300 Blackout cartridge, a system weight not to exceed 5.5 pounds, extended length not to extend 26 inches and length with stock collapsed or folded to be 17 inches, with the weapon fully functional when collapsed or folded. The kits also needed to include a 5.56 mm barrel that allowed the weapon to be changed from .300 Blackout to 5.56 mm in less than three minutes.

The .300 Blackout provides several tactical differences when compared to the 5.56 mm. First, while most 5.56 mm operational projectiles fall within the general range of 55 to 77 grains, the .300 projectile falls within the general range of no to 120 grains. At a comparable velocity, that translates to more energy on target.

Additionally, on the subsonic side, the .300 Blackout provides a fully suppressible cartridge that is not available in 5.56 mm. Many gun and ammunition manufacturers believe that the combination of increased performance in the supersonic range and subsonic capabilities combined to "popularize" the .300 Blackout for many special operators, with potential benefits from the 5.56 mm conversion kit ranging from the availability of training ammunition to addressing possible "shoot house" restrictions.

Meanwhile, Special Operations Command elements continued to explore optimized barrel lengths and barrel twist rates for the .300 Blackout in a potential short-barrel carbine configuration.

Sig Sauer responded to the 2017 Personal Defense Weapon program with a version of its MCX "Rattler." The command subsequently acquired approximately 340 of the guns with 5.5-inch barrels in .300 Blackout, with the ability to convert the guns back to 5.56 mm, according to Jason St. John, senior director...