Final answer:
Early machine guns, including the Maxim gun, could fire between 400 to 600 rounds per minute, this advancement in firepower profoundly changed military tactics and the nature of warfare during World War I.
Step-by-step explanation:
Machine guns, which were one of the most impactful weapons during World War I, underwent significant technological advancements during this time. Early machine guns, like the ones based on Hiram Maxim's 1884 design, could fire between four to six hundred rounds per minute. These weapons were essential in changing the nature of warfare, transforming how infantry attacks were conducted and resulting in mass casualties. For instance, the Maxim gun, which was the first recoil-operated machine gun, had the capacity to fire 600 rounds per minute, showcasing the machine gun's devastating power on the battlefield.