Developed by some of the same engineers who designed the AR-10 and AR-15 family of rifles, the Stoner 63 was one of the world's first modular, adaptable assault rifles used by the U.S. military.
It saw only limited fielding, but was popular among Navy SEALs during the Vietnam war. The Stoner could be configured as a rifle, carbine and light machine gun, firing from a traditional M16-style box magazine or from a belt.
Navy SEALs in Vietnam. Note the Stoner 63 in the center. (National Archives)
The Stoner is surely one of the coolest looking rifles of the conflict, and while beloved by frogmen for years, it was found by some to be too complex and maintenance intensive for general battlefield use.
Fast forward almost 40 years and U.S. rifle manufacturer Knights Armament has updated the Stoner 63 with a new ultra-lightweight machine gun variant that's causing some buzz on the interwebs.
The Stoner X-LMG. (Photo link from The Firearm Blog)
Dubbed the Stoner X-LMG, the new machine gun fires a 5.56mm round from an open bolt with a piston operating system. Knights says the X-LMG uses a unique configuration that eliminates the buffer, further mitigating recoil and making it easier to control.
The X-LMG has a Picatinny rail for optics, a M-LOK handguard and a collapsable stock that helps the new Stoner come in at a surprisingly light weight of just under 9 pounds.
"The Stoner X-LMG ... represents a 2kg weight saving over legacy models (including FN Herstal's Mimimi LMG) providing operators with a more streamlined solution suitable for close quarter battle and military operations in urban terrain as well as parachute insertion," according to one defense industry analysis.
Reports suggest the new Stoner is gaining interest among foreign special operations teams, including Dutch and French commandos and paratroop regiments. Knights armament is already popular among U.S. special operators and is primarily known for its SR-25 and Mk-11 rifles for designated marksmen and snipers.
Here's former Delta Force operator Larry Vickers giving a detailed look at the Knights Armament Stoner LMG — the slightly heavier version of the X-LMG.