Yes, machine guns were used in WW2.
machine guns and rifles
Did you want to know what calibers were used in machine guns or perhaps what cartridges are for machine guns only.
All sides already possessed them before the war.
Well, isn't that an interesting question! Machine guns were first invented in the 19th century, around the 1860s. They have certainly evolved a lot since then, but it's fascinating to think about how far we've come in terms of technology and innovation. Keep exploring and learning, there's always something new to discover!
Efficiency
it used machine guns
Machine guns were first used in the trenches of the First World War. They were mainly used as defensive weapons because they were too heavy to carry, and they required three or so men to operate them. The first true rapid fire gun, the Gatling gun, was used after the Civil War in engagements against Indian tribes.
All of the major players possessed machine guns by the outbreak of the war.
Every country
All of them.
Used extensively.