The M60 - "The Pig"

The M60 machine gun was a weapon that seemed fine in theory but for soldiers in Vietnam terrible design defects were obvious. The bipod and the gas cylinder were permanently attached to the barrel, so quick barrel changes after firing bursts of 200 rounds proved extremely difficult during a contact. To handle the barrel, the Number 2 on the gun required a heat-protecting mitten, which was often lost on patrol or in a contact. Finally, key components in the operating group, such as the firing pin, were prone to fracturing. Unsurprisingly, the gun came to be known by frustrated soldiers in Vietnam as "the Pig'.' A lighter version of the gun, designated the M60E3, was subsequently produced but it was actually no great improvement. It did have a non-removable gas cylinder supporting the bipod, and the new barrel had a carrying handle so barrel changes were quicker and easier. However, the new lightened gun was actually less reliable; the light barrel would burn out if 200 to 300 rounds were fired on fully automatic, so it had to be changed after 100 rounds in rapid fire.