This is another future article for your review. As always, comments are welcome. Many of you, like me, have had hands-on experience with this submachine gun in the military. Hope you enjoy it.

John

U.S. M3 and M3A1 submachine guns



As World War II began and as the United States entered the war on December 7, 1941, our country’s inventory of military weapons was sadly lacking. Not the least of our problems was that our main submachine guns, the Thompsons, had origins dating back to the early 1920s. These were excellent and reliable guns, but quite heavy with forged steel frames and not really suited for mass production. In the meanwhile, the Germans had developed a second generation of submachine guns, the folding stock MP 38 and the subsequent similar MP 40. These could be turned out rapidly because of their stamped sheet steel receivers, and were considerably lighter than our Thompsons. Being compact when their stocks were folded, they were also better suited for cramped quarters such as inside tanks. The British were using U.S.-manufactured Thompsons, but saw the German precedent and began to manufacture their own somewhat crude but lightweight Sten submachine guns in 1941. Both the German and British guns fired the standard European 9mm Parabellum cartridge. In the United States, Thompson production could not keep up with demand, so our military went to work designing our own lightweight stamped steel subgun that would be chambered in our standard .45 ACP caliber. The result of these efforts was the M3 submachine gun. Because of its obvious similarity to a common automotive lubrication tool, it was quickly nicknamed the “grease gun.”

In October 1942, the U.S. Army Ordnance Board, seeing the trend set by the German MP 38s and MP 40s and the British Stens, began a study to develop a similar gun for the U.S. Originally it was to fire either the .45 ACP or .30 Carbine cartridges either in full-auto or semiautomatic mode. However, the Aberdeen Proving Ground found the carbine cartridge too powerful for a blowback weapon locked only by the mass of the bolt and the power of its recoil springs. The semiautomatic requirement was later dropped, due to a slower rate of fire in the full-automatic mode. George Hyde of General Motors’ Inland Division was instrumental in developing the design. Frederick Sampson, Inland Division's chief engineer, was responsible for all tooling and production.

The .45 caliber M3 subgun was formally adopted quickly in December, 1942, and was a startling departure from the Thompsons. It cost the government about $20.00 in 1943 dollars. Its receiver was crafted into a tube shape from stamped and welded heavy gauge sheet steel. The trigger and retractor housings were likewise made from sheet steel. The 8-inch barrel was screwed into the front of the receiver. The heavy steel bolt was backed by twin recoil springs, and the firing pin was nothing more than a projection machined into the face of the bolt. The gun was a straight blowback design made to fire from an open bolt. Pulling the trigger released the bolt to jump forward, stripping a round from the magazine, chambering it, and firing it as it slammed home. Firing in full automatic mode only, the gun would continue to fire as long as the trigger was depressed and there were cartridges in the magazine. The sear would hold the bolt to the rear when the trigger was released unless the ammo in the magazine was exhausted, at which point the bolt would be in the forward position. The bolt could be retracted manually by a prominent spring-loaded lever assembly on the right side of the receiver. A spring-equipped ejection port cover was employed, and when placed down over the ejection port, it served as a safety. The sights were fixed; the rear sight was a simple stamping with an aperture in it. A retractable heavy wire shoulder stock was employed.

While the gun was chambered for the .45 ACP cartridge, it could be easily converted to 9mm with the use of a magazine adapter and changing out the bolt and barrel with 9mm versions. The M3 fed from a 30-round double-column single-feed magazine, mimicking the type used on the Stens. These were not quite as reliable as the double-position feed of the Thompsons, which required less energy to strip a round into the chamber. The rate of fire was a comparatively slow 350 – 450 rounds per minute, compared to some models of the Thompson, which could push to 725 RPM. With its slower cyclic rate, the M3’s trigger could be “tapped off” for single shots if needed. The gun weighed 8.15 pounds, compared to the Thompsons, which weighed from 10.45 to 10.75 pounds, depending on the model. Overall length with the stock extended was 29.8 inches, and when pushed forward, the total length was a handy 22.8 inches, making it very suitable for tank, engineer and aviation crews. The gun could be slung using the standard M1 carbine canvas sling.

The M3 was used throughout World War II, supplementing the more prevalent Thompsons which remained the standard SMGs. The “grease gun” was generally satisfactory but it had one main design flaw. The retracting lever mechanism was both complex and somewhat fragile, resulting in some unfortunate failures in combat. The solution to the problem in December, 1944 was both simple and ingenious. In the newer M3A1, the retracting lever was dispensed with entirely, replaced by a single finger hole for the right forefinger in the bolt, accessible through a larger ejection port. Inserting a finger into this hole allowed the user to retract the bolt back so it could be caught by the sear. Another nice touch for the newer gun was that the bolt and recoil springs could be removed for cleaning from the front by simply unscrewing and removing the barrel. The older M3 required removing the retractor housing from the upper receiver for this. Additional changes were a stock plate and magazine filler being added to the wire stock, and an oil can incorporated into the pistol grip. A longer barrel ratchet spring was used for more positive retention of the barrel, and the magazine catch was provided with a guard to help prevent inadvertent release of the magazine. Weight of the M3A1 was a reduced 7.95 pounds. The gun illustrated for this article is one of the original WWII M3s. The M3A1 saw little (if any) combat action during WWII, but was used extensively in Korea and Vietnam.

The Guide Lamp division of General Motors made approximately 646,000 M3s and M3A1s from 1943 to 1945 during WWII. A version of the M3 that incorporated a sound suppressor in the barrel was developed, with about 1,000 being produced during the war for the OSS (Office of Strategic Services), the forerunner to the present day CIA. After the war, a curved barrel was developed for clearing tanks and transport vehicles from the inside and for shooting around corners. A cone-shaped flash hider was also developed, suitable for both the M3 and the M3A1. About 33,200 M3A1s were produced by the Ithaca Gun Company of Ithaca, New York during the Korean War to supplant those guns left over from the WWII era.

M3s and M3A1s, sometimes produced outside the U.S., have been used by 18 other nations at one time or another. M3A1 submachine guns continued to see some use by our armed forces into the late 1980s, and as late as the Gulf War were still in inventory with engineer units attached to the 1st Armored Division. Originally designed to be cheaply made and thrown away when worn out, they were a surprising mainstay component of our combat forces for many years. Collectors of Class III (legal full-auto firearms) treasure them. Such collectors should be prepared to part with thousands of dollars, endure federal paperwork, and purchase a federal tax stamp. All this to own a gun that originally cost about $20.00! Some semiautomatic look-alikes with longer legal 16.5-inch barrels have been made for those without the inclination and/or funds to purchase the originals. Some semiautos in “pistol” form with no stocks have been made with 8-inch barrels. The originals occupy a milestone position in historic U.S. small arms weaponry, and are indeed classics.

(c) 2016 JLM

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- Cogito, ergo armatus sum -

John--I enjoy these articles as much as ANY I have ever read from the gun legends like Keith, Jordan, Skelton, O'Conner, etc.

John

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Possum—The other white meat!

Great article and information. Thanks for sharing.

I really enjoy your contributions.

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Eccentric old coot

My Old Man (on the left, with the Grease Gun) said he never liked this submachine gun because it was so short you couldn't lean it up against anything like a rifle. Said he kept a Garand in the truck.
He also said as a result of yucking it up in the photo with this German headgear both him and his buddy got head lice.

I enjoyed the write up as always. One sentence seems out of sequence.

"It was designed to fire in blowback mode from the open bolt position.

How about:

The gun was a straight blow back design made to fire from an open bolt.

Just a suggestion to make the design more clear.

Thank you for posting these articles. I look forward to the next one.

BLM

Nice article, thanks for sharing. I only got to shoot one once but liked it. I was amazed at how cheaply it was made and still worked.

Thanks for the suggestion. Good point.

Best,
John

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- Cogito, ergo armatus sum -

John: Very good article. I have owned both the M3 and the Sten MKII and used them in competition at Knob Creek. My M3 came from the Beaumont (TX) PD after having served in England. It was covered in very worn black paint-like coating in 45acp... and had been proofed in 45 in UK. The Imperial War Museum could find no record of the Brits using 45 as the recoreded lend-lease guns had been in 9mm. Also, they did not start the black coating until about 1950. So, no explanation...

In practice the M3 was incredibly reliable and would feed anything I offered up. Single taps were very easy as the cyclical rate was in the 450 range on my gun... a little slower than the Sten. The M3 bolt was quite a bit heavier than the Sten which made the point of impact a little less controllable than the Sten.

I also owned an inert MP40 and was able to compare the quality of construction. As you know the Stens were built in a cottage industry of kitchen tables all over the country. The M3 clearly showed the quality of General Motors head and tail lamp construction. The MP40 was even slightly better.

Alas, all 3 guns are gone now but turned out to be excellent, excellent investments. Thanks.

I appreciate the articles you do on these great old guns.

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Randy
Provenance nerd

In Thailand in 1972 while at MCAS Rose Garden (Nam Phong), I watched our Armorer destroy all of the M3A1's we had in our armory. He used a sledge hammer to smash them flat. Tried to talk him into giving me one, but no dice..........

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USMC 69-93 Combat Pistol Inst.

My active duty Army unit kept ours until mid-1998, replaced by iron sight M4 carbines.

Another great article John!

I'm well acquainted with the old Grease Gun. To make a long story as short as possible. Late 1972 to 74, I was the driver of a M578 Recovery Vehicle in 2nd Armored. I was supposed to have a 1911, but we didn't have enough. After breaking the stock on three M-16A1s, our armorer found me a M3A1 for a personal weapon. I carried that for about a year and a half. It was a hoot!

My Father was a Sargent in a Combat Engineer Battalion in the ETO in WW2. He hated the weapon and said he could shoot his .45 faster than the grease gun.

Informative article on a gun that was junk. It might have been
good for kicking in doors but not much else other than personal
protection. Was handier than a 16 for going through hatches.
It would be a hard choice if it was 1911vs M3. The quality of them was of throwaway type. I cut my finger badly on grip
seam on one of them.

Leon Uris didn't think much of it in his book "Battle Cry".

Thanks for the article though. Interesting.

You sure about that? I read Battle Cry, seems to me they were bad mouthing the Reising submachine gun, not the M3.

You might be right. Read it a long time ago.

I think this sentence (see brackets below) is in error. By the time of the Korean War, the M-3 was far more prevalent than the Thompson, at least among US forces.

[Thompsons were still more prevalent as the standard subguns.]

Also, I'd spell out "gauge" rather than use "gage."

If the Thompson was still more prevalent by Korea, it contradicts all I've read about the matter for decades. You should say why you feel that way, if so. Did you mean that the Thompson remained more common in WWII? Clarify.

Otherwise, nothing bad jumped out at me. But I skimmed the article pretty quickly. I did enjoy it; I'm just in a rush tonight.

I do not normally do Beta reader work, but for you, I'll make an exception. I like your articles and photos.

Good article and well written as usual.

I have only owned one fully auto weapon.
A S&W model 76.

Perhaps a write up is in order since this is the S&W forum ??

A fun little gun that ate everything i fed it. Mostly bought cases
of the cheapest ball ammo i could find with real brass.
Fiocchi was used mostly IIRC.
The 76 also fired from an open bolt.
Also i believe the S&W 76 was actually carried by the Seals at one
point. Someone correct me if i'm wrong.

Chuck

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They hold no Quarter

As a former Tanker, TC and Master Gunner, I carried the M3 along with a chest holstered 1911 for several years before being reclassified. Still miss those days in the TC hatch and all that youthful splendor. Still have my old tanker boots to keep the memories fresh in my mind.

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Dan Ortego ~

Never fired a Riesing, have handled them. Gun wasn't junk, just
not a good combat design. Not a throw in mud gun. There were
a lot of M3s in RVN, not to hard to come up with if you wanted
one. Thompsons were a different story, very scarce. Guys that
had them had to sleep with them. Most got passed to a buddy
when owner DEROSed. A lot of guys had chopped m2 carbines.
Some outfits were strict on non issue weapons. Ours didn't care
what extra you were toting as long as you had issue too. When
you are sitting on Quad 50 or Duel 40mm it was nice to have
a shorter weapon than M16, and the ability to haul them around.

Thanks for the article. Hadn't thought about those old guns in a while. I was a TC in the Central Highlands of RVN in '69. We always had two loaded M3A1s secured in clips welded to the inside of the turret of our M48A3 tank. We also carried our issue 1911A1s. Rightly or wrongly, we had more confidence in our issue pistols than in the SMGs should the need arise. I guess in our minds, the two SMGs were really Really last ditch weapons. Fortunately the situation did not arise. We did a lot of shooting, but mostly with 90MM, .50 and 7.62 coax.

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NRA Life, COTEP 640

I don't know much about theses M3's so it was an interesting read.
Great article...thanks.

3rd paragraph is overlong.. might find a place to break it up, would make it easier to read. hth.

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be safe,enjoylife,journey well

Nice.

A terribly underrated gun, IMO. I think due to its lack of sex appeal.

I wasn't in the military but have shot a few M3s.

One was suppressed and the noise of the bullets hitting steel
plate targets was louder than the gun firing.

The M3 is the most controllable subgun I've shot due to the slow
cyclic rate. Next would be the Madsen M50 in 9mm. It's rate of
fire is faster but the 9mm bullet is lighter so the controlability is still
good.

And then there is the scene in "The Dirty Dozen" where Lee Marvin cuts the climbing rope with one.

I never got to fire one but carried one while on guard duty. This was 1960 and I was stationed in Germany and assigned to a nike battery. The gun was assigned to a friend and everybody was borrowing it when they had to "pull" guard duty. It sure beat carrying the heavy garrand.

Great article. All the time and thought you put into it and some one is critical of a sentence or a paragraph break. Give me and you a break.

Thank you and more like this please

My first agency purchased M3s in 1963 for $29.00 each. Each weapon came new/un-used in a separate cardboard box covered in cosmolens (sic). Neat weapon but loading the 30 round magazines by hand was a chore.
I always thought that there had to be loaders for these weapons ??

I was training Sgt. rookies learned how to reload magazines while I demonstrated shooting the M3 and Thompson, that is the easy way to go!

Thanks to all who posted constructive comments for possible changes to the article. I have re-written the article and made minor changes for readability and clarity on some points. I appreciate you guys - it's always good for me to float a draft for comments.

Best to all,
John

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- Cogito, ergo armatus sum -

I have fired a S&W 76 SMG. It belonged to a cousin of my wife's, who lived in Ohio. His property covered quite a few acres, and he had a "backyard" range. It was quite controllable.

The 76 was in fact pretty much a copy of the Carl Gustav Model 45, and it is that gun that you probably recall as being used by the SEALS in the Vietnam era.

I don't presently plan an article on it - but if anyone has one within 25 miles of Phoenix, I would like to arrange to photograph it. PM me?

John

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- Cogito, ergo armatus sum -

The M3A1 had a magazine loading assist as part of the wire stock.

The double-column single-feed mags are way harder to load than the double-column alternate-feed type as typified by Thompson mags.

I have owned a MAC-10 open-bolt semiauto; these guns and their full-auto cousins used M3 mags, slightly altered to be usable in them. I had a magazine loading device for them, and it sure made it easier than using my issue thumb.

Interesting progression of the double-column single-feed mag. The original trendsetter was the German MP 38, then the MP 40/42s used it also. The Sten mag was a copy of that design, the M3 mag was a copy of the Sten version, and the MAC 10 continued to use the M3 mag primarily because it was cheap and widely available. It would have made more sense to modify the MAC to use modified Thompson mags.

Note that the M3 mags invoke a "traffic jam" of two columns of cartridges coming together toward the single feed point, and then the friction at that feed point is much more than an alternate-feed design, which puts pressure on only one side.



John

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- Cogito, ergo armatus sum -

IIRC-this was the US version of the "Swedish K" or Carl Gustav. I had the loan of Swedish K for a while in 'Nam-and I saw individuals with grease guns, I think Rangers mostly-but never fired or carried one myself. John-you could add something about the use of the grease gun in SEA, as posted above, to complete its service record. JM2CW.

I'd like to know more about this...

The Germans experimented with curved barrels for their MP 38s and MP 40s, and also for the StG 44 assault rifle. Our Ordnance Corps developed a similar barrel for the M3/M3A1. The idea was to allow soldiers inside a vehicle such as a tank to poke the gun from a hatch or other opening and "sweep" the outside of the vehicle from enemy soldiers.

An alternate usage was to shoot around corners - this was an inexact science, although some efforts were made to craft a crude periscope-like optical sight for such use. These barrels wore out very quickly; the whole scheme was never a sterling idea.

John

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- Cogito, ergo armatus sum -

Not much I can add. I have seen a few pictures of them in use during the Vietnam War. Conversely, I have seen numerous pictures of Thompsons (usually M1 or M1A1 versions) in use. One of the pictures was of my high school buddy, Army aviator Lt. Ed Cribb, posing on the tailgate of a truck in 'Nam in the early '60s with an M1A1 Thompson; his widow showed it to me. Perhaps others could relate more about the use of the grease guns there than I could.

John

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- Cogito, ergo armatus sum -

The arms embargo to the USA by the Swedish cut off the supply of the M45 Swedish K ,so SW made the M76 clone for the Navy op's. I have shot grease guns and they are very good Smg's. The M3 was a sturdy reliable and inside 75yards a sure killer!

...that I bought from an ARVN for $25.00 MPC. It was the complete set ; five mags, a chest carrier bag, flashhider, cleaning kit, all in good nick. Of course, I couldn't being it home.

Much later, my unit taught a USAR course in MOS 19E ( Abram's crewman) and found that it was still the authorized crew weapon.

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Long Barrel
Retired Artilleryman

He's submitting this for consideration by an editor. Professional writing is very demanding.

For over 30 years, I wrote professionally for gun and other magazines. I can tell you, editors who pay out cash for material are usually very demanding. Minor errors can easily result in a rejection or a story being sent back to the author for corrections...often with scathing editorial comments.

And writing a book is even more demanding. One has to remember everything in prior chapters, lest he write something that conflicts. Selling a novel is about as chancy as becoming a successful actor or singer.

If the text had been allowed to stand as was, sharp-eyed readers would have challenged the part about the Thompson being more common by the time of the Korean War.
And the other member's comment about a long paragraph would have been noted by an editor and either "fixed" or sent back for improvement.

Col. Chas. Askins told me that readers are far more likely to write to an editor if they see something to complain about than if they like a story. And if you read a book where the author thanks all the friends and secretaries who helped him to proofread it or made other suggestions, you'll have an idea of just how difficult professional writing is.

Spelling knives as "knifes" won't get you kicked off of a gun forum, Lord knows. But if an editor saw a prospective writer do that, he'd have the same reaction as you, when a cop, presumably had when you saw a felony in progress.

I was present when another writer misspelled "gauge" in an article for, The Dallas Morning news. He wrote "guage" instead of "gauge." The editor said some things that showed full contempt and rejected the article. I was then writing a gun column and other free-lance material for the outdoors page and other areas of the newspaper and I took that to heart. I didn't want to be the next poor soul who made an error like that.

John asked for help and he got it, for free. There was no intention to nit-pick or denigrate either him or his material.

BTW, "someone" is just one word.

Back for a moment to the "Swedish K". The K means Kpist, an abbreviation for kulsprutepistol, meaning submachinegun or machine pistol. The Carl Gustav M/45 was popularly known as the Kpist M/45. So "Swedish K" simply means Swedish submachinegun.

I remember back in the late 1950s, for a brief time someone was selling a legal Kpist M/45 in the USA that fired only blanks. I remember reading about it, but no other details. Maybe someone knows more.

I have heard Kpist pronounced as Kaw-Peest. Correct or not, I can't say, as I know nothing about Swedish pronunciation.

If you want to be a writer, don't worry about the grammar and spelling too much, that is the editors job. I consider my editor my partner in every article I write. Any editor who jumps on you for something minor in an article is one you don't want to work for.

I feel we desperately need writers who have something worthwhile to say.

Interesting. I had a Thompson in-country, it was no big thing. Just used it for picture taking or impressing new guys and REMF's. Never took it outside the wire. The old sarge had an M3, it was strictly a picture taker too. Accumulated a couple M2 carbines also. We could carry anything we wanted, but were required to take our M-16 and basic load any time we left the wire. Given the stifling heat and everything else we had to hump, I didn't take anything more than I had to. Wound up giving all that swag away or turning it in to the armorer. Had I known how easily I would slide thru Customs on the way back to the world, I would've brought something with me. Oh well.

When I got to SETAC, we were all lined up outside the customs
area. Word came back the line they were searching everything.
We all started throwing contraband in a dumpster. No one wanted
any hassles at this stage. We got in building and they hardly
looked at anything. I would liked to have had the job of cleaning
out that dumpster. I wouldn't doubt that happened to every
plane load. I know more than one 1911 went into it.

Yikes!

Steve McQueen used one and he's the king of Kool.

Another good "Grease Gun" movie is the Australian flick from 1982 "Attack Force Z." An then-unknown Mel Gibson stars, and his little special ops group uses suppressed M3s.
The US Army SFOD-D (Delta Force) used M3s in their formative years, 1979-early 80s, as they were pretty much restricted to what was in the supply chain.
The April, 1980 "Desert One" aborted Delta Force Iranian hostage rescue mission resulted in a plane/helicopter crash in the Iranian desert. Some of the pictures of the aftermath show burnt M3s in the aircraft wreckage.

__________________
John

One of my friends had a dewat M3 in college that he paid $25 mail order. The good old days. When he heard about the Amnesty, he was going to reactivate the M3 and register it. The M3 was lightly dewatted by welding the chamber and one small weld to keep the barrel from being unscrewed from the receiver and could easily be cut with a hacksaw. He even bought a new barrel. Then the M3 disappeared. He is still convinced that his college roommate stole it and registered it for himself. My friend still has the new barrel for the M3.

As another retired tanker, I have more than a passing familiarity with the grease gun. In 20 plus years, all of the guns I saw in the Army, except two, were produced by Guide Lamp. I did see one Ithaca produced M3A1 in a Wisconsin National Guard arms room in the Eighties and another on a Form 4 for sale by a vendor at Knob Creek 20 some years ago.

It is my understanding that the Army surplussed some M3's, with the cocking handle, to PD's and such during the Fifties. Those guns are, relatively speaking, the version most commonly available. Very few transferable M3A1's are out there. The Ithaca I saw was an "amnesty gun" that got papered in 1968.

The "grease gun" was part of the vehicle equipment, AKA "BII" (basic issue items) on tanks, recovery, and armored engineer vehicles. When As a First Sergeant in the 1st AD, I carried one in the field (in addition to my 1911) because my Arms Room had a couple to spare and the Armorer worked for me.

During the first Gulf war, many Armor units had the good fortune to still be armed with the M1911A1 as the infantry had the priority for the M9.

In RVN, the MPs on Long Bihn unsuccessfully tried to "confiscate" grease guns from my tank crew as "unauthorized." As was mentioned earlier, the Thompson was much coveted, and I passed mine on to another tank commander when I DEROSed. The tank made it much easier to carry such useful additions outside the wire, although it did work well for the obligatory "hero" shot to show the grandkids.

Attached Images

Tommy gun.jpg (36.4 KB, 47 views)

There was a separate loader for the M3. Among other improvements, the M3A1 had a magazine loader made as part of the stock. On both guns the stock also doubled as a cleaning rod. The barrel nut on the M3A1 included "flats" so the stock could be used as a wrench to loosen it. The oiler was also different, clipped to the side of the M3 and integral to the pistol grip on the M3A1.