Complex sentence: Starting in the 1840s, with the advent of the Minié ball and the first military breech-loading rifles, the weapon entered the age of industrialised warfare, where it was mass-produced and accessible to all infantrymen.
Split into simpler sentences: Starting in the 1840s, with the advent of the Minié ball and the first military breech-loading rifles, the weapon entered the age of industrialized warfare. It was mass-produced and accessible to all infantrymen.