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Developed in the early 1970s to replace the impending loss of capability with the decommissioning of the Iowa-class battleships and the Des Moines-class heavy cruisers. The Mark 71 Major Caliber Lightweight Gun (MCLWG) was developed to be fitted to the proposed strike cruisers and to be refitted to selected destroyers.

The Mark 71 is a single barrel adaptation of the triple barreled Mark 16 8-inch/55 found on the Des Moines-class cruisers. The prototype gun mount had a weight of 86 tons and was roughly 20% heavier than the Mark 42 5-inch/54 it would replace. The prototype could fire up to twelve rounds per minute from a 75-round automatic ready service magazine for fixed ammunition when operated by one man. A specially modified Mark 155 computer provided 8-inch/55 ballistics for the Mark 68 gun fire control system. The Mark 71 mount would have a elevation of -5/+65 degrees (30 degrees per second) with a traverse of -160/+160 degrees (also at 30 degrees per second) with a maximum range of 32,000 yards.

Technical evaluation occurred aboard the USS Hull (DD-945), a Forrest Sherman-class destroyer in 1975, with operational testing through 1976. The Operational Test and Evaluation Force determined that inaccuracy made the gun operationally unsuitable, and concluded the lightweight 8"/55 gun would be no more effective than a 5-inch/54 gun firing theorized Rocket Assisted Projectiles, which ultimately never materialized. The report recommended against production or installation of the lightweight 8-inch/55, and program funding was terminated in 1978.

The USS Hull was used for weapon testing from 1975 to 1978 and was the only destroyer ever to be fitted with a 8-inch gun. The mount was removed in 1979 and is now at the Naval Surface Warfare Center in Dahlgren, Virginia.