Polymer projectiles are nothing new. The .50 BMG's on Dad's B-17 used frangible Bakelite bullets for gunnery practice against various target planes such as P-40's that made simulated firing passes at them during air to air gunnery training. The gunners were told not to fire at the cockpit area, just the armored rear sections of the target planes. Prior to getting frangible ammo, they fired at a long cloth sleeve towed by the target plane. His gunners liked to shoot at the tow rope and try to cut it.
Jerry
