In 1885, William C. Endicott, President Grover Cleveland's Secretary of War, was tasked with creating the Board of Fortifications to review seacoast defenses.
The findings of the board illustrated a grim picture of existing defenses in its 1886 report and recommended a massive $127 million construction program of breech-loading cannons, mortars, floating batteries, and submarine mines for some 29 locations on the US coastline.
In the overall system, it was an intermediate caliber between the heavy 8-inch, 10-inch, and 12-inch weapons and the small 3-inch guns intended to defend minefields against minesweepers.
Within a few years, it was realized that operating the disappearing carriage negatively impacted the rate of fire, and the M1900 low-profile pedestal mount was designed.
To quickly arm some works a few weapons were purchased from the United Kingdom including nine 6-inch Armstrong guns, two of which survive at Fort DeSoto near St. Petersburg, Florida.
Between the Endicott program and the 1905–15 Taft Board fortifications, approximately 200 6-inch guns were emplaced in the United States and its possessions, around 150 of which were on disappearing carriages.
One survives on a field carriage in the collection of the U.S. Army Ordnance Training and Heritage Center, Fort Gregg-Adams, Virginia.
In June 1919, after the Treaty of Versailles was signed, the field carriages for the 6-inch guns were declared obsolete and almost entirely scrapped.
Many 6-inch weapons (most of them stored since World War I) were remounted on M1 through M4 shielded barbette carriages at new locations in two-gun batteries to complement the 16-inch guns.
[13] Some additional 6"/50 caliber ex-Navy guns were mounted in the year after Pearl Harbor to provide some defense while the new batteries were under construction; locations included Alaska, American Samoa, and Suriname (formerly Dutch Guiana) among others.