The Mark 12 5"/38-calibergun was a United States dual-purpose naval gun, but also installed in single-purpose mounts on a handful of ships. The 38-caliber
until replaced by the standard widespread dual-purpose 5"/38calibergun, which was derived from the 5"/25. Guns removed from battleships were probably converted
Knox-class frigates) 5"/38calibergun US predecessor 5"/54 caliber Mark 16 gun US predecessor 5"/54 caliber Mark 45 gun US successor QF 4.5inch Mk I - V naval
Atlanta's 5-inch/38-calibergun with the new 5-inch/54-caliber Mark 16 gun. The new gun had a higher rate of fire and a longer range than the 38-calibergun, and