Complex sentence: During World War II, Armour-Piercing Capped projectiles were found to be unstable in flight, so rounds were developed with a ballistic cap called the'Armour-Piercing Capped Ballistic Capped'.
Split into simpler sentences: During World War II Armour-Piercing Capped projectiles were found to be unstable in flight. So rounds were developed with a ballistic cap, called'Armour-Piercing Capped Ballistic Capped'.