The Lightweight Small Arms Technologies (LSAT) program is a ongoing United States military joint-service initiative seeking to develop the next-generation of infantry small arms and their applicable ammunition types. The program began in 2004 and has since produced a Light Machine Gun (LMG) prototype platform to fire two distinct types of ammunition - one caseless and the other polymer-cased. The United States Army began actively testing the LMG in 2012 which resulted in AAI Corporation (Textron) being awarded a development contract for continued work on the technologies.
The LSAT Light Machine Gun is a product of this testing period. It saw design work begin in 2003 as a potential new Warfighter weapon. It sports a conventional external arrangement with a recoil-reducing shoulder stock, underslung pistol grip and trigger unit, and forend integrating Picatinny accessories rails. The barrel protrudes a manageable distance ahead of the weapon's body and is capped by a slotted brake. A hinged, folding bipod is affixed to the forend and optics are set over the receiver.
The weapon weighs under 10lb when empty and has an overall length of 36 inches. The barrel comes in two lengths, 16.5 inches and 12.5 inches, the latter making the LSAT a much more compact and manageable form reducing both overall length and operating weight.
Internally, there is a gas-piston system with push-through feed-and-ejection. The weapon is chambered for 5.56x45mm NATO in a cased or caseless form. It can reach 650 rounds-per-minute , has a muzzle velocity of 920 meters-per-second, and an effective firing range out to 1,000 meters. The feed system involves a 100- or 150-round (cased telescoped or caseless cartridge, respectively) along full-polymer linked disintegrating belts pulled from a soft ammunition pouch.
In 2018, the United States Army began looking for a successor to the storied M249 SAW (Squad Automatic Weapon) (based in the Belgian Fabrique Nationale FN "Minimi") with the work completed on the LSAT LMG making it an ideal candidate (a 7.62mm development has also been completed and tested). A new program has been drawn up for this requirement, succeeding the LSAT program as a result.