Rifleman Q&A: U.S. Model Of 1928 Thompson Variants

by
posted on January 27, 2023
** When you buy products through the links on our site, we may earn a commission that supports NRA's mission to protect, preserve and defend the Second Amendment. **
Thompson

Q. I was reading an auction catalog, and a reference was made to an American military Thompson submachine gun. It stated it was a “1928 Colt Navy overstamp, not a Savage.” The catalog made that verbiage seem important. What’s the significance of the “overstamp,” and were there other military 1928 Thompsons besides the Navy guns?


A. In 1928, the U.S. Navy made plans to officially adopt the .45 ACP Thompson submachine gun but requested a few modifications from the original Model of 1921 design. Specifically, the Navy mandated a lower rate of fire (approximately 600 rounds per minute instead of 800), a horizontal fore-grip instead of the vertical type used on the 1921 and a Cutts compensator.

This latter feature had been available by special order on Thompsons for a couple of years. It helped to hold down the muzzle during firing by deflecting the muzzle blast upward. With these changes, the “U.S. Navy, Model of 1928” submachine gun was adopted. An order of 500 was placed with Auto-Ordnance, which along with the 340 M1921 Thompsons acquired previously, was enough to satisfy the limited demands of the U.S. Navy and Marine Corps for the foreseeable future.

Model of 1928 Thompson Submachine Gun calibre .45 Automatic Cartridge

The Colt-made U.S. Navy Model of 1928 Thompsons are fairly well known. Savage’s early Thompsons were marked “Model of 1928” even though they were procured under government Model of 1928A1 contracts.

While not an extremely large number, the Navy order did a great deal toward keeping the fledgling and struggling Auto-Ordnance Company alive. It is interesting to note that the guns needed to fill the Navy order were from the original batch of 15,000 guns made by Colt for Auto-Ordnance in 1921. Indeed, these Colt-made guns were sufficient to meet the demand for Thompsons until the eve of World War II. The Model of 1921 marking had the “1” over-stamped to “8”, but, except for the addition of a heavier actuator to reduce the rate of fire and the horizontal fore-grip, the M1928 U.S. Navy Thompson retained the same features as found on the commercial Thompsons of the same era.

The U.S. Army had shown less interest in the Thompson than the Navy. It wasn’t until September 1938 that the Thompson was changed from “Limited Procurement” to “Standard” and designated as the “Submachine Gun, Caliber .45, Model of 1928A1,” and 1928A1s were made by Auto-Ordnance and Savage. Very early versions of the 1928A1 made by Savage are marked “Model of 1928,” even though they were procured under government contract as M1928A1s.

—Bruce N. Canfield


This “Questions & Answers” was featured in the March 2007 issue of American Rifleman. At time of publication, "Questions & Answers" was compiled by Staff, Ballistics Editor William C. Davis, Jr., and Contributing Editors: David Andrews, Hugh C. Birnbaum, Bruce N. Canfield, O. Reid Coffield, Charles Q. Cutshaw, Charles M. Fagg, Angus Laidlaw, Harry Hunter, Chuck Karwan, Charles E. Petty, Robert B. Pomeranz, O.D., Jon R. Sundra, Jim Supica, John M. Taylor and John Treakle. 

To subscribe to the magazine, visit the NRA membership page and select American Rifleman as your member magazine.

Latest

LCP Max Magpul 01
LCP Max Magpul 01

The LCP Meets Magpul: Ruger's LCP Max with Magpul's EHG

Over the years, Ruger has enhanced its LCP with the introduction of the LCP II and LCP Max. New for 2026, Ruger is offering a new version of the LCP Max with the addition of a Magpul Enhanced Handgun Grip.

Review: 945 Industries Q.A.P. Series Off-Body Carry Bag

Off-body carry can be somewhat controversial, but choosing the right gear can go a long way toward successful carry. One good option is the Q.A.P. Series of bags from 945 Industries.

At 75, CCI is Offering Even More

In 2026, CCI Ammunition—formally Cascade Cartridge, Inc.—marks its 75th anniversary with a fitting tribute to innovation and American ingenuity.

Gun of the Week: Powder River Precision Rubicon Icon

Powder River Precision has taken the basic Ruger 10/22 rifle concept and enhanced it with its Rubicon Icon design.

The Armed Citizen® May 1, 2026

Read today's "The Armed Citizen" entry for real stories of law-abiding citizens, past and present, who used their firearms to save lives.

Training & Gear for Active Shooter Response

For armed civilians, developing an active-shooter response plan isn’t about playing hero. It’s about having the right gear and the skills to decisively use them if violence finds you.

Interests



Get the best of American Rifleman delivered to your inbox.