lightest existing ammunition to fire standard bullets comprised caseless varieties. The Heckler & Koch G11 was the only weapon to achieve a service capable assault rifle firing caseless ammunition. Its unique ammunition, designed by Dynamit Nobel, introduced several important innovations, such as improved internal ballistics through the use of a primer, and the prevention of cooking off (the lack of a case makes it easier for a hot chamber to ignite the exposed propellant) through the use of the less sensitive hexogen/octogen as the explosive component. The Advanced Combat Rifle experimental program gave the US Army access to the ammunition and entrenched the ammunition as a viable option. With the high efficiency and lethality of the ammunition, the vast expenditure such a concept had needed for development, and the reduced risk of using an already proven ammunition design, the LSAT program chose a licensed version of Dynamit Nobel's caseless ammunition as a route towards its goal of weight reduction. The LSAT program also uses the same concept of a rotating chamber as the G11 (albeit, the LSAT LMG chamber swings around a longitudinal pivot. whereas the G11 chamber rotated around a horizontal axis at its very centre). Polymer casing for ammunition had already been developed and produced, and it provided the second route for achieving weight reduction. While a polymer case could never be quite as light as no case, the risks involved in the use of polymer ammunition were less, due to its similarity to present ammunition and the reduced heat load on both the weapon and the ammunition's propellant. Further budding technologies, such as alternative barrel materials (such as ceramics), and the increased efficiency and size reduction of telescoped ammunition (used by the G11 and other developmental weapons), also formed the basis for the LSAT program. Program In 2004, the Joint Service Small Arms Program created the Lightweight Machine Gun and Ammunition program to compare conceptual, lightweight machine guns and ammunition designs by two teams of companies. The team of eight, led by AAI Corporation had their design chosen over the design of the General Dynamics-led team. In 2005, the project was replaced with the Lightweight Small Arms Technologies program to place the emphasis on developing technologies for a wide range of small arms. The earlier Lightweight Family of Weapons and Ammunition concept is visible in the new program. The cohesive team of companies is combined with government