Silent But Deadly

The High Standard Model HDMS

By Brian M. Briones

Article published on: December 1, 2025 in the Winter 2025 edition of Army History

Read Time: < 5 mins

Composite image above: William J. Donovan, shown here as a major general, the director of the Office of Strategic Services. National Archives

The failure of the United States to anticipate the attack on Pearl Harbor, Hawai'i, led President Franklin D. Roosevelt to approve the creation of the Office of Strategic Services (OSS) on 3 June 1942. Maj. Gen. William J. Donovan, a highly decorated World War I Army officer, was appointed as its director. Under Donovan, the OSS utilized research, analysis, covert operations, counterintelligence, espionage, and technical development to gather and use intelligence to give the United States an edge over its enemies.1 A silenced weapon—one equipped with a noise reducer or suppressor to muffle the telltale sound of a firearm—was needed to help agents complete their often clandestine missions.

On 22 November 1943, a contract was awarded to the High Standard Manufacturing Company of New Haven, Connecticut, for 1,500 silenced U.S.A. Model HD pistols in .22 long-rifle caliber. High Standard already had produced thousands of the .22-caliber semiautomatic pistols for the U.S. military to use for basic pistol instruction. The Model HD used a ten-round detachable box magazine, was accurate, and had a relatively small report and minimal muzzle flash when fired, making it a great platform with which to work. The design was modified by drilling forty-four one-eighth-inch holes one-quarter inch apart from each other in the barrel. During testing, this modification was found to be the magic number that allowed for enough propellant gas to be collected to provide sufficient noise reduction while still allowing the weapon to cycle and chamber the next round. The silencer itself consists of a roll made from twenty tin-plated bronze screens soldered together, a brass washer, and a stack of 110 tin-plated bronze screen disks. The screen roll, disks, and brass washer are contained in a 7.75-inch steel tube .98 inches in diameter. It screws onto the frame where it meets the base of the barrel. The silenced pistol was designated the Model HDMS. It was 13.815 inches long and weighed 2 pounds, 15 ounces. To reduce the risk of corrosion and increase the weapon’s resistance to wear over time, the earliest production pieces had blued frames and Parkerized silencers. Later examples were entirely Parkerized. The silencer reduced the sound of firing the weapon by 90 percent. General Donovan was so pleased with it that he demonstrated the pistol to President Roosevelt in the Oval Office.2

Regular deliveries of the HDMS began 20 January 1944, and, just a week later, it was demonstrated in Algiers. On 1 February 1944, General Douglas MacArthur received twenty of them, six of which went to the 6th Army Special Reconnaissance Unit, the Alamo Scouts. By summer 1944, the HDMS was regularly available to OSS field stations.3The OSS weapons catalog listed the HDMS as being quieter than traffic noises and closing doors. Additionally, the pistol was advertised as having no muzzle flash, making it perfect for working indoors and in the dark. All this without any reduction in performance.4The suppression of sound and muzzle flash would degrade, however, the more the weapon was fired. Regular cleaning of the weapon was suggested after every twenty rounds.5The screen roll in the silencer also would foul after repeated use. The pistol was shipped with a replacement screen roll to be used after 250 rounds were fired.

.22-caliber High Standard Model HDMS, right side

HDMSs that were delivered to the OSS were stamped with “PROPERTY OF U.S.” and the Ordnance Department stamp. Central Intelligence Agency models did not have these stamps.

.22-caliber High Standard Model HDMS, left side

As the war progressed, so did the HDMS’s reputation. It became one of the most common weapons used by the OSS. The Alamo Scouts even used it to hunt for food while working in enemy territory. By war’s end, the U.S. government had purchased 2,620 Model HDMS pistols.6After the end of the war and the dissolution of the OSS, a production run was completed for the Central Intelligence Agency.7Despite its small caliber, the HDMS proved to be an excellent weapon for close-range sniping and sentry elimination, particularly when silence was key.

The silencer on the HDMS could be removed for cleaning. The silencer consisted of a metal cylinder containing a mesh tube, mesh washers, and a brass washer. The endcap has been removed in this photograph. The Model HDMS was shipped with a replacement mesh tube.

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