Here are a few more downloadable files from DTIC. These cover the LFWA program: Lightweight Family of Weapons and Ammunition. This covers attempts at aluminum and plastic cartridge cases, enhanced propellants for smaller cartridge cases, and caseless cartridges.
Be warned, a couple of these .pdf are huge. You are better off trying to save the files directly to your harddrive, especially if you have a Dial-Up Internet connection.