5-inch/38-caliber gun

5-inch/38-caliber gun. The 5-inch/38-caliber gun was a dual-purpose naval artillery piece developed for the United States Navy in the 1930s. Renowned for its reliability, high rate of fire, and versatility, it became the standard secondary and anti-aircraft battery for American warships during World War II and the Korean War. Its widespread deployment on vessels from destroyers to battleships made it one of the most successful naval guns of the 20th century.

Design and development

The Bureau of Ordnance initiated development in the early 1930s to create a modern dual-purpose gun capable of engaging both surface targets and aircraft. The design team, leveraging lessons from the earlier 5-inch/25-caliber gun, prioritized a rapid, semi-automatic firing cycle and robust construction. Key features included a horizontal sliding-wedge breech and a power rammer, which allowed a well-trained crew to achieve a high sustained rate of fire. The associated Mark 37 director provided advanced fire-control for long-range anti-aircraft engagements, integrating radar like the Mark 12 and Mark 22 sets during the war. Production was led by the Naval Gun Factory in Washington, D.C., with additional manufacturing by companies like Bethlehem Steel.

Operational history

Entering service aboard the USS *Farragut* in 1934, the gun saw its first major combat during the attack on Pearl Harbor. It formed the primary anti-aircraft defense for the United States Pacific Fleet throughout pivotal battles like the Battle of the Coral Sea, Battle of Midway, and the Naval Battle of Guadalcanal. The weapon was ubiquitous on *Fletcher*-class, *Gearing*-class, and *Sumner*-class destroyers, as well as on cruisers like the *Cleveland* class and battleships like the *Iowa* class. It proved devastating against Japanese aircraft during the Great Marianas Turkey Shoot and provided crucial naval gunfire support during amphibious assaults at Tarawa, Iwo Jima, and the Okinawa campaign. It continued service through the Korean War and on some vessels into the Vietnam War.

Variants

The primary production variant was the **Mark 12**, mounted in single and twin enclosed mounts (**Mark 30**, **Mark 38**). The open **Mark 21** mount was used on destroyer escorts and auxiliary vessels. Post-war, the **Mark 32** was a lightweight single mount developed for smaller ships. The twin **Mark 28** mount was an early design used on some pre-dreadnought battleship modernizations and the USS *Wichita*. These variants were integrated with different fire-control systems, such as the simpler Mark 51 director used on many landing craft and merchant vessels.

Specifications

The gun fired a fixed 127×680mmR cartridge weighing approximately 70 pounds. The projectile itself weighed 55 pounds, with types including Armor-Piercing (AP), High-Explosive (HC), and VT proximity-fuzed anti-aircraft. Muzzle velocity was 2,600 feet per second. Maximum surface range was about 18,200 yards, while its anti-aircraft ceiling was 37,200 feet. The gun could elevate from -15 degrees to +85 degrees, with a traverse of nearly 360 degrees on most mounts. A typical crew consisted of 15 to 18 men.

Surviving examples

Numerous examples are preserved as museum pieces and memorials across the United States and abroad. Notable displays include mounts on the USS *Massachusetts* in Fall River, the USS *Alabama* in Mobile, and the USS *Midway* in San Diego. Others are found at the Washington Navy Yard, the National Museum of the United States Navy, and the Battleship Cove museum. Many are also displayed as standalone monuments in towns across America, often donated by the United States Navy to American Legion posts and Veterans of Foreign Wars halls.

Category:Naval guns of the United States Category:World War II naval weapons Category:127 mm artillery