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Ask Frank

We are sorry, our well known friend and machinegun researcher and author Frank Iannamico, has had to discontinue this column due to other pressing commitments. You can still check Frank's website for your questions and for his list of publications and other information of interest to Thompson as well as all machinegun enthusiasts.

Dear Frank,

Could you tell me if you know where I could get an original finned barrel for a Thompson 1928A1? I know that Ohio Ordnance has one that they want $450 and another place that has them for $350. The ones that are currently available from the factory are just not correct.


Hello Diane,

Just a year or so ago you would have had a somewhat difficult time locating a Thompson barrel. However, since the "like new" parts sets have been coming in, finding a decent barrel is much easier and cheaper. There are a number of sources to check to include: Phil Askew, Ohio Ordnance, IMA, Keystone, and even TCA members.
Good luck in your quest.


Dear Frank,

First , your Thompson books are top shelf! So informative and interesting. I will be purchasing American Thunder II.

My question is, were the Auto Ordnance, West Hurley M1 models ever parkerized from the factory? If so, what color?

Thanks much,


Dear Don,

The West Hurley M1s all came from the factory a flat blue/black color with dull blue barrels. However I have seen a number of them that were redone by the owners with the military gray-green color to achieve more of a military appearance.


Dear Frank,

I have a 1928 West Hurley. Production was some time around 1982 or 1983 I believe. The problem I am having is with my magazines. Most of them seem to fit rather loose in the gun. I checked the mag catch I do not think it is the problem. What I noticed is that the slot or key ways in which the mags slide up in is always loose to the mag.

With this condition the mag can rattle around in the well. In turn the gun miss feeds occasionally. I was having a problem even when using a drum but that was remedied when I put GI internals in the gun. Next was a ramping problem. The fed ramp had a sharp edge so I polished a radius on it, and deburred the rest of the feeding area.

The real question I guess is it normal for the mags to fit loose in the well, example the mags can wiggle right to left a lot.

Thank you,


Dear David,

A very common problem with West Hurley manufactured Thompson was with the magazine catch. This often contributes to feeding problems. If your magazine catch is not of GI manufacture I suggest that you replace it.

As far as the magazines being loose, I would suspect that your frame may be slightly out of spec but many original Thompson’s share this same problem. I would try new a GI catch and spring as suggested it may very well solve both of your problems.


(Editor's note: I did minimal changes to Jean's letter below. I thought it was important to show how much a dedicated Thompson owner was willing to struggle with a foreign language to achieve the desired results with his Thompson. I regret we could not have been of more help to Jean. Jean, we salute your efforts.)

Dear Frank,

In a flea market I found a Thomson 1927 A3 chamber for .22LR; old of 1968 like new, but in France I can't found the drum magazine for it, I have the 30 round magazine with the adaptor, it no so good than Drum. How I found this, and how cash for this, I buy for the gun 350$. Thank you for a French guy, I am very so proud to shoot with my Tommy Gun. (Editor's note: The following is Jean's reply for clarification.) Tank you, yes I look for THE DRUM magazine for their, or how to modify a 10 round drum. I have a 20 rounds modify by adjonction of a 10 small magazine into it.

Encore merci pour tout,


Dear Jean,

It would be very difficult to modify a 10 round drum into a larger capacity. I can only suggest locating a factory made high-capacity drum.


Dear Frank,

I have a Thompson that I bought back in 1966. It is in excellent condition and I have fired it only about 20 times. (Less than a thousand rounds) I believe it was brand new and unfired when I got it. The only markings on it are: THOMPSON SUBMACHINE GUN CALIBER 45 M1 No 213913 and on the reverse, AUTO-ORDNANCE CORPORATION BRIDGEPORT, CONNECTICUT. U.S.A.

It is legally registered. I am interested in selling it legally and was wondering how to go about putting it up for sale and about how much it is worth. I was told by a dealer that it is somewhat of a rare animal in that it has a floating firing pin. Any info you can provide would be much appreciated.


Dear Dennis,

If you originally purchased your Thompson back in 1966 I suspect that your investment has grown substantially. It is difficult to estimate a price on a Thompson without seeing it, but it is currently a sellers market with M1 versions selling as high as $15,000.00.

The M1 was produced in smaller numbers than the M1A1 variation, but the M1 is not particularly rare on the C3 market place and would not bring any substantial premium over the M1A1. The most important thing to most buyers is condition.


Dear Frank,

First let me congratulate you on your fine work on the Thompson gun American Thunder! This book is an outstanding reference that I have found most informative and helpful. (Editor's note: American Thunder II is coming out soon).

I have owned for a number of years a nice WW2 vintage M1A1 made by AO that I have been trying to estimate an approximate date of manufacture. The weapon's serial number is 386413. It is still in what I believe to be the original "dulite" dull black finish. and has the "U.S. property" stamping behind the rear sight wings. The A1 stamping appears to have been added as it does not align perfectly with the M1 stamping. This leads me to suspect (per your book) that my Thompson may have been upgraded to M1A1 standard during it's service life.

Can you provide me with an approximate date of manufacture based upon your expertise or data base of thompson guns ? Any information that you might provide would be greatly appreciated.
All my best,


Dear Jammie,

The A1 stamping on most Auto-Ordnance Bridgeport M1A1 looks "added" because of the Ordnance Department’s initial rejection of the M1 models produced there. The problem was that the cyclic rate of fire exceeded the maximum specification established for the M1. By the time a waiver letter was issued, the M1 had been superceded by the M1A1 model. As a result the M1s were upgraded to the M1A1 specification and hand stamped to reflect the change before the guns left the plant.

The exact date of manufacture is difficult to estimate, but based on the records that I have (and are in American Thunder) I would say that your Thompson s/n 386413 was made in March or April 1943. Remember there could be a difference in the manufacture VS shipping date.


Dear Frank,

I'm “The Virtual Tommy Smith” and just removed a barrel from a torched MIA receiver! I managed to get the barrel off, but it took several hours. I wonder if you had any experience that could be useful to our readers. See my column for my "austere/brute force" method.


Dear VTS,

I have found that the easiest way to separate barrels from receiver remnants is with a mechanic's air hammer, also known as an air chisel and/or “muffler tool”. Secure the barrel, and place a blunt tool into the air hammer, and use it against the receiver. The air hammer will exert a lot of force and 99% of the time loosens the receiver. It sometimes helps to clean the receiver with solvent and let it soak for a week or so in a good penetrating oil such as Kroil. If the barrel STILL will not loosen try heating the receiver remnant with an acetylene torch. A hand held propane torch will not get hot enough.
Doug Richardson’s barrel wrench works VERY well, on complete receivers, but on remnants there usually isn’t enough receiver left to secure it in the tool.

If you are removing a stubborn barrel that is scrap, simply weld a ¾” nut on the muzzle and spin it off with an air wrench.

If the receiver was ever Parkerized with the barrel intact it can be VERY difficult to loosen.


Dear Frank,

The M1 and M1A1Thompsons were purposely made without a compensator. Do you think the elimination of the compensator was warranted?

Mr. Cutts

Dear Mr Cutts,

The military did a lot of testing and evaluation of the Cutts compensator used on the Thompsons. Surprisingly early testing (1920 era) found the device quite effective, while later trials during World War II found that the Thompson was more effective without it!
At an Ordnance Committee Meeting held 10/29/42, using Aberdeen Proving Ground Report No. 205 OP 5082 it was decided that...
“Greater accuracy could be obtained without the use of a compensator. Numerous tests have found that the compensator adds nothing to the reliability, functioning or accuracy of such a weapon as the submachine gun. It is the opinion of the committee that compensators are not required on submachine guns”.
It was recommended by the committee that no more compensator testing be done, and that on future production of submachine guns no compensators be used.
The rest is history...


Dear Frank,

Why are the West Hurley M1 submachine guns considered a C & R firearm, while the 1928 style is not?


Dear Curious,

One of the criteria for a modern firearm to be added to the BATF Curio and Relics list is the number produced. There were only 609 West Hurley M1s made while there were 3,219 WH 1928 Models produced. The small number of WH M1’s manufactured aided in qualifying it for the C&R list.
Don’t get discouraged, the modern Smith and Wesson Model 76 submachine gun is also on the C&R list with approximately 6,000 units produced.

To get a modern weapon listed on the C&R list it takes some effort. I suggest obtaining a copy of the BATF’s Curio and Relic manual and reading their requirements for getting a modern firearm added to the list. Some of the West Hurley commemorative 1928 Thompsons are already on the C&R list.
In my new book “United States Submachine Guns” I have reproduced letters that I received from WH A-O, listing the year and total Thompsons they made.

Good luck!


Dear Frank,

Why did the military favor the 30 round stick magazines over the 50 round drum?

Little Drummer Boy

Dear Drummer Boy,

The drums were not well suited for a military application, many were discarded by troops after the emptied them. The reason? They were heavy, awkward to carry, difficult to reload in the field, and easily damaged. They were also expensive generally $4.00 compared to a 30 round magazine that cost around .27 cents during the war.
I have read documents that reveal the British did not want the drums that they had, and sold them to the U.S. on a reverse Lend Lease. The U.S. government ended up destroying all of them.


Dear Frank,

I have a Bridgeport (A-O) Model 1928 Thompson S/N 133XXX. There are no acceptance marks on the upper receiver and the US mark has been ground off. I have heard that this gun may have been covertly supplied to the British or another ally; hence, the lack of markings. What do you think?

Perplexed Bridgeport Owner

Dear Perplexed Bridgeport Owner,

There were a number of A-O 1928 Thompsons that have had the US markings carefully ground off, as well as having the 1928A1 overstamped to read “1928AC”, additionally, the weapon’s serial number usually had a letter X added. While there has been no hard evidence discovered to date, it is believed that these “AC” Thompsons were taken from A-O’s production for police sales. I have seen several 1943-1944 documents that revealed that there were several 1928’s with serial numbers that had an X suffix. In one case the department still had the Thompsons, and they did have the US removed but with the AC overstamp. Usually, there are no A-O or military proof marks on the receivers of these guns. This would indicate they were never sold to the military. (Editor's follow-up: the Thompson in question did have the "AC" overstamp but not the X suffix.)


Dear Frank,

Why is it some West Hurleys (WHs) shoot perfectly, but mine seems to be a "jam-o-matic"?
In a Jam

Dear Jam,

When WH Thompson production began they were assembled with many GI Thompson parts. As the GI parts supply began to dwindle, WH began to make their own parts, which often were not up to GI standards. One common part that caused many feeding problems was the WH magazine catch. Check all of your parts for a small letter stamped on them, indicating a US GI part. I would suggest replacing all of the internal WH parts with genuine GI parts.


Dear Frank,

Some of my Thompson's parts are marked with a squared off S. Who made the part?

Square Shooter

Dear Shooter,

The squared off, or block style, letter S indicates that the part was manufactured by the J. Stevens Company of Chicopee, MA. The Stevens Company was owned by Savage who was the primary contractor for military Thompson production.


Dear Frank,

If you were in charge of the Ordnance Bureau during WW II, would you have picked the M3 over the Thompson if price were not an issue? And why?

Tommy the Historian

Dear Tommy,

The M3 scored much higher than any other submachine gun tested by the Ordnance department, including the M1, M1A1 and 1928A1 Thompsons.
The reason the M3 had a high score was its ability to function during the mud and dust tests. The M3 bolt rides on two metal rods mounted inside of the receiver, the bolt never actually touches the inside of the receiver. This system makes the M3 very reliable. The main problem with the M3 was its double-stack single feed magazine. It’s hard to load and the design is unreliable.
The cyclic rate of the M3 is much slower than that of a Thompson, but it was exactly what the Ordnance Department wanted. The M3 however is fun to shoot. Because of its slow rate of fire, it is easy to walk the M3 onto a target without aiming.
To answer your question...In a serious life or death scenario, I would choose a Thompson, I don’t like the slow cyclic rate of the M3, nor its hard to load magazine.


Dear Frank,

What is the highest serial number Thompson made during WWII?

The Gambler

Dear Gambler,

That would be a presentation grade M1A1 Thompson serial number 1,244,194 (the very last Thompson made in February, 1944). The serial number represents the TOTAL number of 1928s and M1-M1A1s made by Savage from 1940-1944. The weapon was presented by Savage to the Springfield Armory Museum in 1978.