armored cow: [origin: Australia, WW2] canned milk
army strawberries: [origin: Africa, US, WW2] prunes
balls: [origin: US] midnight on a 24-hour; it looks like four balls (0000)
beans and bullets: [origin: US] term for all types of supplies
beat your face: [origin: US] to do push-ups, usually as punishment
BFO: [origin: US] blinding flash of the obvious
bumf: [origin: UK] Paperwork, especially busywork; from "bum fodder" (fit only to be toilet paper)
butterbar: [origin: US] 2nd lieutenant or ensign, reference to rank insignia (single gold bar)
cat eyes: [origin: US & Canadian army] helmet-band with 2 pieces of reflective material on the back
See more, including the less PG-variety: HERE