By: Warren Gray

Copyright © 2023

“Men react one of two ways when they are shot at. If you just

shoot at them, they will take cover and return fire, but if you

start hitting them, they withdraw.”

— Veteran, Navy SEAL team leader, discussing the need for an accurate, light machine gun

Today, in the 21st century, the lightest machine gun in widespread use by the U.S. Armed Forces is the combat-proven FN M249 Para in 5.56mm NATO, at 16 pounds, with a 16.3-inch barrel (or 13.7-inch barrel on the European, FN Minimi Para version). But it wasn’t always that way. In fact, during the Vietnam War, U.S. Navy SEALs used the lightweight, Stoner 63A (XM207E1) Light Machine Gun (made by Cadillac Gage) in 5.56mm NATO, at just 11.68 pounds with a 20-inch barrel, or the Stoner 63A1 Commando (Mk. 23 Mod. 0) version, at 10.5 pounds with a 15.7-inch barrel. A 150-round, drum magazine was the preferred choice in battle.

Navy SEAL in Vietnam, with Stoner 63A1 Commando LMG. Photo credit: U.S. Navy

These lightweight weapons were designed in 1963 by Eugene Stoner, formerly of ArmaLite (which is still in business), the very same man who designed the AR-7 survival rifle in .22 LR, the AR-10 battle rifle in 7.62mm NATO, and the AR-15/M16 assault rifle in 5.56mm NATO. He was assisted by L. James Sullivan and Robert Fremont in this endeavor, and the light machine guns were quite successful in combat, but production ceased in 1971 as the war was winding down.

Stoner founded his own company, ARES Inc., that year, and in 1986, he introduced the ARES LMG-1 (Stoner 86) light machine gun, weighing only 12 pounds, but it was never adopted by any military services. In 1990, Stoner joined Knight’s Armament Company (KAC), and developed the KAC Stoner LMG (Stoner 96) in 1996, a belt-fed, light machine gun tipping the scales at just 9.9 pounds, with a 12.5-inch barrel! Stoner died in 1997, but KAC continued improving his LMG product, finally introducing the KAC LAMG (Light Assault Machine Gun) in 2017.

KAC LAMG, 2019 model (Photo by KAC)

The new KAC LAMG weighs 11.4 pounds, with a quick-change, 15-inch barrel, and is a belt-fed, air-cooled, light machine gun, firing from an open bolt for improved cooling, and utilizing the Constant Recoil system that was originally designed for the Ultimax 100 light machine gun, designed in 1978 by Stoner 63 contributor L. James Sullivan, resulting in extremely light recoil, and therefore superb controllability.

The innovative KAC LAMG has not been officially adopted by any military service yet, but Danish and French Special Forces apparently tested an LMG-A1 version with 14.5-inch barrel in 2017, just before the LAMG was introduced, and the photo below shows two U.S. Army Rangers in Afghanistan in 2021, with one of them carrying a newer KAC LAMG in flat dark earth (FDE) finish.

This is where the story takes an interesting turn, because Eugene Stoner’s colleague, Jim Sullivan, designed another very lightweight machine gun, the hugely successful Ultimax 100, for Chartered Industries of Singapore (CIS), which became ST Kinetics in 2000. Produced in eight different variants since 1982, the Ultimax 100 is a very popular weapon, in service with at least 16 nations worldwide, including Bosnia & Herzegovina, Croatia, Indonesia, Peru, Serbia, Singapore, Slovenia, Thailand, and the U.S. Army Special Forces.

The most widely produced version, the Mk. 3 or 3A, weighs only 10.8 pounds with a standard, 20-inch barrel, and somewhat less than that in Ultimax 100 Para form, with a 13-inch barrel, so this is actually slightly lighter and shorter than the KAC LAMG, easily taking the coveted title of “The World’s Lightest Machine Gun.”

It has a side-folding stock, quick-change barrel assembly, threaded barrel for fitting a suppressor, and a 100-round, synthetic, drum magazine. Firing from an open bolt, the “Constant Recoil” design allows the bolt-carrier group to travel all the way back without ever impacting the rear, instead stopping gradually along the axis of movement against the resistance of the return springs. This feature results in extremely low recoil, and a very accurate and controllable weapon. There’s also an optional, 10.5-inch barrel for VIP protection duty, making for a very handy weapon with fearsome firepower.

The latest version is the Ultimax 100 Mk. 8, produced since 2020, and weighing 11 pounds with an 18-inch barrel standard, and a revised, folding stock.

Recognizing the need for a very lightweight, controllable, and accurate machine gun, the U.S. Special Forces have been unofficially using Ultimax 100 Mk. 4 and Mk. 5 Paras since at least 2016, instead of the heavier, bulkier FN M249 Para used by the infantry.

U.S. Special Forces soldier in Afghanistan, with Ultimax 100 Mk. 4/5 Para. Photo credit:

According to The Firearms Blog (TFB) in 2016, “The photo (above) is a bit confusing. The camo is Navy AOR1, which is typically the camo of choice for Navy SEALs. However, due to the helmet and plate-carrier design, as well as the American-flag patch on the chest, the person in the photo is actually (U.S. Army) Special Forces. The chest rig is called SFLCS (SF Load-Carrier System).”

These two exceptionally lightweight machine guns, the KAC LAMG and the Ultimax 100 Para, are amazing examples of firearms technology, both designed with significant input from Jim Sullivan, and therefore very similar in purpose and features. The Ultimax 100 is lighter by a small margin, but both of these fine guns have certainly proven their worth in battle with U.S. special operations forces, and other nations around the world.

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Warren Gray is a retired, U.S. Air Force intelligence officer with experience in joint special operations and counterterrorism, and is an NRA member. He served in Europe and the Middle East, earned Air Force and Navy parachutist wings, four college degrees, and was a distinguished graduate of the Air Force Intelligence Operations Specialist Course, and the USAF Combat Targeting School. He is currently a published author, historian, and hunter. You may visit his website at: