In 1951, the Army developed the Special Purpose Individual Weapon, which fired plastic-cased 12-gauge rounds filled with multiple flechettes in an attempt to increase the probability of hitting enemy targets.
The Advanced Combat Rifle program, launched in 1986, pursued a similar goal, with several of the prototypes featuring plastic-cased ammo.
The Army took a renewed interest in lightweight ammo after 9/11, when combat troops began to struggle under heavy combat loads in Iraq and Afghanistan.
Despite years of research and development, the Army's weapons and equipment are still too heavy to allow foot soldiers to maneuver safely under fire. The only way to fully realize lightweight concepts is to take lightweight polymer composites for cartridge case applications.
A pointed steel projectile with a vaned tail for stable flight.
The minimum mission-essential equipment required to fight and survive.
In the last 30 years, combat loads have skyrocketed.