A U.S. Marine looks over his shoulder at the blazing thatched houses of Duc An, 60 miles south of Da Nang, after a raid on the village on Aug. 6, 1965.

10. M14
Type: Semi or Fully Automatic Rifle
Caliber: 7.62 x 51 mm (.30 inch)
Muzzle Velocity: Approximately 2,799 feet per second
Rate of Fire: 700–750 rounds per minute

By the end of World War II, with an American infantry platoon carrying as many as four different weapons -- and four types of ammo -- the U.S. Army decided to develop a single weapon that could fulfill multiple roles. The result was the M14. First fielded in 1957, the rugged, accurate new rifle had plenty of stopping power with the standard NATO 7.62 mm round. It first saw major action in Vietnam, where soldiers liked its performance but struggled with the weight of both gun and ammunition. Before long it was phased out in favor of the lighter M16, but a few frontline units still use the classic weapon, primarily as a sniper rifle.

VIDEO: See an M14 in action.
PUZZLES: Put together these combat rifle puzzles.