The two most common assault rifles in the world are the Russian AK-47 and the American M16. These Cold War rivals have faced each other in conflicts both large and small since the early 1960s. They are used by military, police, security forces, revolutionaries, terrorists, criminals and civilians alike and will most likely continue to be used for decades to come. As a result, they have been the subject of countless comparisons and endless debate. This article explores the history, philosophies and the issues behind these debates in a chronological, measure vs. countermeasure format.