Just as the War On Terror was getting underway, the U.S. Army Special Operations
Command (USASOC) created the Special Purpose Rifle - Variant (SPR-V) program to
fill the need for a modular assault rifle capable of shooting 5.56 in addition
to 7.62x39mm. With barrel and bolt switched, it was to fire 7.62x39mm from
indigenous AK-47 magazines. It needed to retain the characteristics of the M4
and remain compatible with the Special Operations Peculiar Modification (SOPMOD)
accessories. Robinson Armament produced the RAV02 and Knights Armament Corp
produced the SR-47 in response to the USASOC SPR-V solicitation. Ultimately,
the SPR-V program was rolled into the U.S. Special Operations Command (USSOCOM)
Special Forces Combat Assault Rifle (SCAR) project, and fell victim to politics.
Even though the project was canceled, Special Forces soldiers had come to
realize 7.62x39mm provided increased lethality over 5.56, especially when
penetrating barriers.
Troubling reports about 5.56's performance were coming back from the field.
Several soldiers had been killed or wounded by Taliban fighters who had already
been shot multiple times by the Americans' 5.56 M4 carbines. These failures to
incapacitate spurred the 5th Special Forces Group (SFG) to design an "Enhanced
Rifle Cartridge" (ERC) to outperform 5.45x39mm, 5.56, 5.8x42mm and 7.62x39mm.
MSG Steve Holland (5th SFG (A)) and Cris Murray of the U.S. Army Marksmanship
Unit (USAMU) led the ERC project to provide optimum terminal performance from an
M4 with minimal changes to the weapon. Troy Lawton (Chief Ballistics
Technician) and Cris Murray (Service Rifle and R&D Gunsmith) of the USAMU
assisted in developing loads, and built the rifles for the ERC project.