during the 1850s there were a number of improvements in weapons, especially rifles. during the civil war, both armies were equipped with rifles that could shoot farther, could reload faster and were much more accurate than the muskets used in the mexican–american war. yet the same military tactics were being used as the earlier war; close formations of men firing in volleys. the new rifles combined with obsolete tactics were responsible for up to 90% of all deaths in battle.