Machine Guns
Machine guns needed 4-6 men to work them and had to be on a flat surface. They had the fire-power of 100 guns and could kill a person up to 400 meters away.
Large field guns had a long range and could deliver devastating blows to the enemy but needed up to 12 men to work them. They fired shells which exploded on impact.
It's impact was so enormous it allowed a handful of men to give off a fire power that previously had needed hundreds to thousands of foot soldiers.