This is far from a complete list
Russia
M1908 Maxim
Vickers
Lewis
Colt
US
Browning
Colt
Chauchat
Austria-Hungary
Schwarzlose
Maxim
France
Chauchat
Used extensively.
rifles and machine guns
machine guns, mustard gas, tanks
machine guns, mustard gas, tanks
All of them. Very popular weapon.
Yes. There were machine guns in WW1. There were Gatlin Guns, a type of machine gun, in the Civil War.Yes
All sides already possessed them before the war.
Machine guns, tanks, airplanes, and poison gas.
Kill people
Everyone. Everyone had them before the war even began.
Mustard and chlorine gas. As well as machine guns.
machine guns were basically used the same way as they are now, but far more dangerous. At the squeeze of a trigger they could fire 500 to 1000 rounds per minute