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What Is An 21/28 Overstamp Navy Gun?

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I am upgrading from West Hurley to Colt. I found a Colt 1921/8 US Navy gun. I don't know anything about these guns.


Since these guns are overstamped, I assume that means they existed as 1921 guns that where upgraded to 1928 specs. That implies that the upgrade was done at the time there was a 1928 model, which I assume is after 1928, or they would not know what to call it.


Did Colt have a bunch of 1921 guns in their warehouse that they upgraded to 1928 models and then sold to the Navy instead of selling the Navy new 1928 guns?


The gun was supposed to be from a police department. Did the Navy sale fall through and Colt sell the guns to the public/police? WHere they sold as Navy contract overruns? Did the PD get it as Navy surplus?

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Yes, AA restamped them and they had a slower fire. It is a desirable gun to have. It is not a matter of deals falling through. Anyone could buy the 28, not just the Navy.



Edited by rsilvers
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Welcome to the Board. The questions you ask can be easily answered in several books now on the market. I suggest you purchase "American Thunder" by Frank Iannamico or "Thompson: the American Legend" by Tracie Hill. You will find everything a beginning Colt Thompson collector will need to know in these books. Briefly, in answer to your question, all 15,000 Colt production Thompsons were manufactured as Model of 1921. The Model of 1928 Navy Overstamp was made by taking in stock Model of 1921 Thompsons and substituting several different parts, most notably a re-designed heavier actuator, so as to reduce the rate of fire. The number 1 in the date 1921 was overstamped with an 8 to make the Model of 1928 Thompson. It sometime looks like 192B. This modification was initially done at the request of the US Navy and resulted in additional sales of Thompsons to the US Navy and US Marines. The US Navy markings were also added to Thompsons sold to customers other than the US Navy. If you will provide me with the serial number of your 1928 Navy Thompson, I may be able to tell you what police department was the original purchaser. Again, welcome and enjoy the best Thompson board on the Internet.


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The Colt Navy 1928, or overstamp 1921, or 28N, were converted from the existing 15,000 1921's Colt made for Auto-Ord. It is the original actuator, not bolt, that was re-engineered by adding more weight, (initially by just riviting the weighted piece to the 1921 actuator), and employing a stiffer spring and one piece pilot/buffer. The initial contract for 50 TSMGs' with this decreased rate of fire was ordered by the U.S. Navy in 1928. This type of Colt TSMG became so popular that police departments also wanted them. If they already had 1921's, they sent them back to Auto-Ord for the new parts and the additional "U.S. Navy" and "8" stamping added to the gun. The Colt Thompson was never marked 1928, without the overstamp. It wasn't until Savage made their so-called commercial 1928 that the overstamping ceased to exist, along with the absence of "U.S. Navy" markings. The standard Savage military Thompson's of WWII utilized this design.
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The replies are very accurate. The 1921 guns used a lighter actuator and a different buffer and buffer pilot. These guns were too fast for the government and wasted ammunition (according to the Navy). They added weight to the 21 actuator and a smaller buffer pilot, buffer and different spring. This slowed the gun down. They then took an "8"marking and stamped it "OVER" the "1." This is where the term stampover (what I call them) and other terms came into being. Overstamp or stampover was the birth of the great military TSMG. This was the first real evolution in Thompsons. For some reason the Navy stampovers sell for more than the regular 21A and 21AC guns do. (The "C" added to the "A" means the Cutts compensator was attached; there were 4 models of Cutts Compensators too).


Basically it’s another Thompson with a few different parts, a slower rate of fire, and a higher price tag.


The 1928 Savage and AO Thompson was the most produced model of Thompson during WW2. Over a million 1928s were produced by Savage and AO. There were less M1 and M1A1 variants made. The numbers are in Frank's book if you want to look it up.


The 1928 Thompson in any variation is the definitive Thompson "look." They take a drum and that look is the most recognizable gun shape in the world bar none.




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