The Thompson Sub Machine Gun (TSMG) would begin its association with the Marine Corps during a demonstration in 1920. Impressed by the Thompson’s capability, Colonel Cyrus S. Radford would privately purchase three TSMGs for the Marine Corps to test in the fall of 1921. Several small orders of Model 1921A Thompsons would be placed in 1923 & 1925, for testing and service in Haiti with the 2nd Marine Regiment. Large scale service would not begin until the fall of 1926 when it was decided that the standard Model 1921A was to be modified to better fit military needs. Marine Colonel Robert Cutts’ recoil reducing compensator was to be attached to the barrel, creating a variant known as the Model 1921 AC.

Instructions from Colonel Cutts on the proper employment of the TSMG with his compensator (NARA).

The first order of TSMGs would be placed on the 22nd of October, 1926, for a total of 250. Of note, not all of these first Thompsons were converted from M1921As to M1921ACs, with a minority of the Thompsons leaving the Auto-Ordnance factory with the desired Cutts Compensator attached. The plan was for the Marine Corps to exchange the M1921As at a later date.

Marine Corps Gazette article from the Winter of 1926 mentioning the adoption of the TSMG (NARA).

In order to protect U.S. Postal Service deliveries from frequent robberies, Marines were dispatched with the TSMG and M1897 Trench Gun supplementing their standard arms. While this duty would only last for several months, it was well publicized. Legends that the Postal Service purchased the first 250 TSMGs for the Marines to guard the mail with have been disproven by archival documentation, but still persist amongst the general firearms collecting community.

M1928 Navy TSMG #5576, one of five shipped from the USMC Depot of Supplies in Philadelphia to the Depot Quartermaster in Corinto, Nicaragua on June 14th, 1928 for service with the 51st Company, 2nd Battalion, 5th Marine Regiment as documented by Gordon Herigstad in his book “Colt Thompson Submachine Gun Serial Numbers & Histories” (Plowman collection).

Early photos of Marines in Nicaragua with pistol grips on their TSMGs (NARA & USMC Archives).

After the first contract, the Marine Corps and its parent Naval Department requested the 900 rounds per minute rate of fire of the M1921s be reduced. This would be accomplished by using a heavier actuator, stiffer spring and single piece buffer, and the rate of fire was slowed to around 650 rounds per minute. These changes would culminate with a new Thompson known as the Model 1928 Navy. As all M1928s were originally M1921s, once the conversion process was complete the last year on the receiver was over-stamped from its existing “1” to an “8”, and “U.S. Navy” markings added above.

KNOWN USMC COLT THOMPSON CONTRACTS

DATE	CONTRACT	MODEL	SIZE
12/23/1921	Small Order	M1921A	2
8/9/1923	Small Order	M1921A	4
5/2/1925	Small Order	M1921A	4
10/22/1926	First Contract	M1921A & M1921AC	250
11/21/1927	Second Contract	M1928 Navy	25
1/6/1928	Third Contract	M1928 Navy	50
1/24/1928	Small Order	M1928 Navy	2
2/25/1928	Fourth Contract	M1928 Navy	200
4/10/1928	Small Order	M1928 Navy	5
5/8/1928	Small Order	M1928 Navy	2
6/14/1928	Small Order	M1928 Navy	5
6/21/1928	Fifth Contract	M1928 Navy	46
6/27/1928	Sixth Contract	M1928 Navy	100
8/21/1928	Nicaraguan Guard	M1928 Navy	10
9/25/1929	Haitian Guard	M1928 Navy	5

Left: Marine 1st Lt Lewis B. “Chesty” Puller and Gunnery Sergeant William “Ironman” Lee with Guardia Nacionale troops in Nicaragua, armed with M1928 Navy’s, one with a pistol grip and another with a straight grip (NARA). Right: Marines in Nicaragua with a variety of weapons: a M1918 Browning Automatic Rifle, a Springfield M1903 with a VB Grenade Launcher, and two M1928 Navy TSMGs. One has a 50 round “L Drum”, while the other has a 20 round stick magazine (USMC).

The Marine Corps would receive a total of 790 Colt TSMGs, 671 through official, known contracts and the remainder through replacement frames and contracts not yet discovered. The vast majority of these Thompsons would see considerable use by the 2nd, 5th and 11th Marine Regiments during the Banana Wars in Haiti and Nicaragua, and the 4th and 6th Marine Regiments in China. Some would be left with National Guard units after the Marines ended these endeavors. In 1957, Interarms was able to import 24 of the Thompsons left for the Nicaraguan Guardia Nacionale by 2nd Battalion, 5th Marines when they departed the country in 1934. Of the 24, only a minority appear to have been registered prior to the Gun Control Act of 1968. One is in the possession of the United States Marine Corps Museum. The remaining few are amongst the rarest documented USMC firearms known to exist.