At a secret arms-design contest in Stalin's Soviet Union, army technicians submitted a stubby rifle with a curved magazine. Dubbed the AK-47, it was selected as the Eastern Bloc's standard arm. Scoffed at in the Pentagon as crude and unimpressive, it was in fact a breakthrough ;a compact automatic that could be mastered by almost anyone, last decades in the field, and would rarely jam. Manufactured by tens of millions in planned economies, it became...