The SR-47 is a modern assault rifle based on the AR-15 family of rifles created by Knight's Armament Company for the USSOCOM. Unlike the majority of guns based around ArmaLite design, the SR-47 fires the Soviet 7.62x39mm round from AK-47 magazines. The rifle was created after soldiers on long missions in Operation Enduring Freedom complained of running out of 5.56x45mm NATO ammunition for their M4 carbines but having plenty of captured AK-47 magazines. The SR-47 is basically an M4 that will accept standard AK-47 magazines rather than NATO STANAG M16/M4 mags, along with other minor modifications common to KAC's designs.
It is speculated that the SR-47 was discontinued because of the glut of AK-47s found in Iraq and Afghanistan and the reliability issue of feeding "dirty" 7.62x39mm ammunition through the AR-15 direct impingement gas system. Personnel issued the weapon in the field also mentioned that the SR-47's action often had trouble feeding and firing rounds from standard AK-type magazines.
After the September 11, 2001 attacks, SOCOM placed an open call for a 7.62x39mm rifle of basic M16 style design. This was known as the SPR-V. Three companies submitted samples: Lewis Machine & Tool (LMT), Robinson Armament, and KAC. After a series of trials, the pack was narrowed down to the RAV-02 Robinson carbine and the KAC SR-47.
The SR-47 is based on the Knight Stoner Rifle (or SR) series. Many aspects of the rifle resemble an M16, but almost all parts are upsized slightly to handle the larger 7.62x39mm cartridge. It uses standard AK magazines and the magazine well is modified to accept standard box magazines.
Only seven rifles are known to exist. Six went to USSOCOM and one was retained in the Knight Co. museum.
The rifle uses a custom barrel manufactured by Obermeyer Barrel Co. of Wisconsin. It is machined to accept a custom Knight manufactured suppressor.