Polymers for Lightweight Small Arms Cartridge Cases

The modern U.S. Army warfighter is being tasked to carry additional gear into the field to enhance combat effectiveness with the penalty of an increased weight burden. Recent improvements in polymer material technology and manufacturing processes that would allow a lightweight polymer to be used as a cartridge case material would help alleviate a portion of this weight burden. Polymer materials are 5 to 7 times lighter than steel or brass and half the weight of aluminum. Polymer materials have additional benefits compared to metals such as long storage life with no corrosion, potentially lower material and fabrication costs, and potential improvement in insensitive munitions performance. Texas Research Institute Austin, Inc. proposes to develop a lightweight, low cost, corrosion free polymer cartridge for small caliber ammunition that will function reliably in existing weapon systems and be capable of surviving the loads, pressures and temperatures experienced during the ballistic cycle. A polymer 5.56mm cartridge case will save over 1 lb of weight for every 100 rounds of ammunition compared to an equivalent brass cartridge case. This reduction in weight will allow U.S. Army soldiers to carry additional ammunition, or other equipment and supplies onto the field.