Battle of the Somme
Larger field guns needed up to 12 men to operate them.  They fired shells which exploded when they hit. The machine guns were a major force for the Germans, who used them to their full effect as the British forces simply walked over no man's land straight into open gun fire. The British did not have access to many machine guns, which made their task even more difficult. The Germans were in a higher position than the British, which gave them the upper hand.