Polymers for Lightweight Small Arms Cartridge Cases

Currently, small caliber cartridge cases are manufactured from brass. Because brass is a critical material, spent cartridge cases must be retrieved from firing ranges, which is time consuming and costly. The motivation to develop a polymer cartridge case is therefore primarily cost based, as it will remove the need for salvage, and will also reduce the cost of manufacture, by employing standard plastic molding techniques. It has also been demonstrated1 that polymer based casings will offer the following advantages: Increased Energy Transfer to the Projectile; Reduce Heat Transfer to Chamber; Reduced Muzzle Flash; Improved weapon feeding; Easier removal of ruptured casing; Reduced weight load for soldiers. The objective of this proposal is to investigate the use of certain some novel thermoplastic cartridge shell casings for small caliber ammunition. These chosen termoplastics have glass transition temperature in excess of 1500 C, moisture intake at saturation of less than 3% and tensile modulus variation of less than 15% over the temperature range from -550 C to 650 C.