What did marines use as a bayonet in Vietnam?

Answer 1

Both the USA & USMC used the M14 & M16 rifle in South Vietnam. Both the M14 & M16 rifles utilized the same bayonet, both bayonets were simply modified differently from each other. The M14's M6 bayonet had its release button near the hand guard while the M16's M7 bayonet had its release mechanism near the rear of the handle and had a larger barrel ring (to slip over the M16's muzzle). Both bayonets used the same scabbard, both had close to the same blade length (roughly 6 1/5"). Both had black plastic handles & the standard parkerized blade (in the Viet War all US military small arms were parkerized).

Answer 2

Marines in Vietnam typically used the M7 bayonet, which was a modified version of the M6 bayonet used in the previous M14 rifle. It featured a 6.75-inch blade and could be mounted on the M16 rifle. The bayonet was designed for close-quarters combat and had a cutting edge on one side and a serrated edge on the other.