Both sides used a much better heavy machine gun than they had used before in Europe. Four to six people worked one. They fired 400 to 600 bullets per minute. The machine guns got too hot and needed water on them. This kind of gun was invented in 1884 by Hiram Maxim. The German version was the MG08. The British used the Vickers machine gun, which was very safe and easy to use. The machine guns changed how war went; and killed many soldiers. Because they sometimes got too hot, they could be slow. In case that one of the crew of the machine gun were shot, the whole squad were trained to fill their spot. As the war progressed, more machine guns were used in trench warfare in combination with barbed wire defensive positions, making them the most deadly weapon on the battle field.