The Probert Encyclopaedia of Warfare

MK-45

The 54-calibre Mk-45 is a US lightweight naval gun based on the older Mk-42, produced since 1971, that provides surface combatants accurate naval gunfire against fast, highly manoeuvrable surface targets, air threats and shore targets during amphibious operations. The Mk-45 has a range of 13 nautical miles and a rate of fire of between 16 and 20 rounds per minute automatic, firing a 5 inch calibre round from a 475 to 500 round magazine.
Research MK-45