M3 and M3A1 Grease Guns

The US began looking for a cost-effective replacement for the Thompson submachine gun in 1942, and the “Grease Gun” was the result. Designed by George Hyde (a noted firearms designer at the time) and Frederick Sampson (GM/Inland chief engineer), it was a very simple and almost entirely stamped firearm. Chambered for the .45ACP cartridge, it is notable for its very low rate of fire – 350-400 rpm, which made it quite controllable and easy to shoot for relatively inexperienced troops.

The M3 was a quite reliable gun (and what problems it did have were mostly due to its single-feed magazine and not the gun itself), but a revision program was begun in April 1944. This would produce the M3A1, which further simplified the design by removing the charging handle (which had been the one mechanical trouble point of the M3 anyway) and replacing it simply with a notch in the bolt to cock the gun with a finger.

While the M3 and M3A1 were replaced in front-line service in 1957, they would remain in military inventory as armament for tank crews and truck drivers until 1992 – quite the legacy for such a crude looking weapon!


  1. “its single-feed magazine”
    This is quite mind-boggling for me – earlier Thompson sub-machine gun use dual-feed magazines, but for some reason there was decision to use single-feed, when dual-feed would not only enhance reliability but also might mean that Thompson and Grease Gun might interchange.

    “While the M3 and M3A1 were replaced in front-line service in 1957, they would remain in military inventory as armament for tank crews and truck drivers until 1992 – quite the legacy for such a crude looking weapon!”
    It also spawned PAM 2 – Argentinian sub-machine gun for 9×19 cartridge, see photo here: http://www.iwm.org.uk/collections/item/object/30029453

    • Interestingly other South American nation – Brazil – produced similar in general characteristic – that is cheap, stamped and with folding stock – sub-machine gun, which fire .45 Auto cartridge and was derived from originally 9×19 sub-machine gun, namely INA 953 which was derived from Madsen M50:

      • And Ronaldo Olive has written an article about the conversion of the pistola metralhadora from .45acp to 9mm!

        During the 1964-85 dictatorship and various leftist urban guerrilla formations, “os anos do chumbo” years of lead, the Minimanual of the Urban Guerrilla by Carlos Marighella extolled the virtues of the INA M50:
        “The ideal submachine gun for the urban guerrilla is the INA .45 caliber. Other types of submachine guns of different calibers can also be used—understanding of course, the problem of ammunition. Thus, it is preferable that the manufacturing capabilities of the urban guerrillas be used for the production of one type of submachine gun, so that the ammunition to be used can be standardized. Each firing group of urban guerrillas must have a submachine gun handled by a good marksman. The other members of the group must be armed with .38 revolvers, our standard weapon.”
        See: https://www.marxists.org/archive/marighella-carlos/1969/06/minimanual-urban-guerrilla/ch05.htm

    • Isn’t the magazine design also what plagued the MP 40 and the Reising M50? And similarly, the Chauchat’s magazine was also the primary problem, not the action itself! Shouldn’t there be a modern successor to the M3 series, given its age? I’m pretty sure tank crews and truck drivers need a handy weapon chambered for NATO standard 9×19 Parabellum. Said successor needs a better set of iron sights and possibly a real charging handle, unless you think that a “two handed reloading cycle” is better than a “one handed reloading cycle.”
      Two-handed reload: left hand changes magazine, right hand pulls the bolt
      One-handed reload: magazine change and charging action done by same hand (I’m pretty sure Denny did this for the AK), regardless of whether charging handle is right-handed or left-handed.

      • “Reising M50”
        In this case problems were caused by fact that parts were NOT interchangeable between different examples – that is if you mixed parts between examples it might not work, unlike most other 1940s era sub-machine guns. Additionally IIRC some users were NOT informed about that fact.

      • “age? I’m pretty sure tank crews and truck drivers need a handy weapon chambered for NATO standard 9×19 Parabellum.”
        Most notably newer sub-machine gun with “magazine in grip” layout and so-called “wrap-around” bolt were developed giving smaller size (see for example Steyr MPi 69). Remember that in cramped AFV interior space is at premium. However some problem might be mating small size with low RateOfFire as second might be easiest done by using long travel of moving parts. Muzzle brake might be also useful for making it more controllable, and if used lowering RateOfFire would be less critical.
        On the other hand different way might be chosen and rather than use sub-machine gun for crew of AFV use intermediate cartridge automatic rifle, but designed to be possible small, like for example Dragunov MA:

    • Odd indeed with the Thompson magazine right there for comparison.

      But if one of the design requirements for the M3 was easy conversion between .45 ACP and 9mm Luger, perhaps the single position feed was a deliberate design choice. I could see how single position feed would simplify a cheap and reliable caliber conversion.

    • The first issue was to U.S. paratroops and Rangers. in fact, the M3’s combat debut was D-Day, as some of the paratroops who jumped into Normandy early on the morning of June 6, 1944 were armed with M3s.

      By V-E Day the M3 was fairly common in tank crews, being more compact than either the Thompson or the carbine.(Folding-stock M1A1 carbines were pretty much exclusive to the airborne forces.) Also, unlike the carbine, the M3 like the Thompson used the same .45 ACP ammunition as the Colt M1911A1 pistol, meaning the tank crew only needed to carry one extra allotment of IW ammunition, not two different ones.

      The M3 was also issued to other vehicle crews, notably truck drivers and other transport personnel.

      In the postwar era, the M3 and M3A1 were frequent export items for “indigenous personnel” in countries receiving MAP (Military Assistance Plan) aid from the U.S. They were especially common with counter-insurgency forces up through the Vietnam era, when the compact assault rifles began to supersede SMGs on the battlefield. The “Grease Guns” remained in service with police forces until the early 1990s, notably in South and Central America.

      Interestingly, during the Philippine civil conflict in the early 1970s under the Marcos regime’, both sides (government and leftist would-be revolutionaries) employed gangs of late teen/early twenties gunmen who carried their weapons in guitar and violin cases (I think they got the idea from watching Warner Brothers gangster movies). They all affected “mod” dress and long hair.

      The “Grease Gun” was the preferred weapon of the leftist gangs, who called themselves “Beatles” (no, really).

      The government’s counter-revolutionary death squads of the same type preferred the selective-fire M2 carbine. They called themselves “Monkees”.

      There were times that the street violence, especially in Manila, resembled a demented Saturday morning kids’ TV show. Except with real blood. A lot of it.



      • eon– It is my understanding, possibly misinformed, that the M3 and later of course, the M3a1 were more common in the Pacific Theater than in Europe? Do you know if that was the case or not?

  2. Boy, talking about a “Blast from the past.”
    Dad, one of the ”Not entirely common’ survivors of the entire WWII participation of the 7th Division Infantry, found, in 1947, needing to support his new wife, (a combat survivor in her own right,) and his new baby, (me.) a need to basically support.
    [Yes, I know, it sounds like a movie treatment, but it comes from the those…days… More another time.]
    After turning down a personal request from Curtis Lemay for a transfer to the then (very) new US Air Force, Dad found himself not only commanding the local mid-west tank company (gotta keep them ruskie paratroops from overrunning Nebraska don’t you know,) but Range Master for the local National Guard.
    Coincidentally, with a lot of practical experience with certain hardwares from .45 up to 90mm. (Actually 106mm.)
    By the time I achieved Cub Scout age, our pack was at least passingly familiar with field trips to the local power plant, the Coca-Cola bottling plant, a really large industrial printing factory, and…much more.
    Some of these field trips were pretty scary for a then, about 8 or ten year old. Occasionally I still have nightmares about the city-block long printing press, or, especially, the packing plant. (Read “The Jungle” by Upton Sinclair for a taste of “why.”)
    Anyway, being the Range Master and all, one day Dad’s Pack ended up st the range where a bunch of then 10 year olds were exposed to a display of .45s, Garand, Carbines, A6s, and…you guessed it, Grease Guns. We didn’t get to shoot them that day, but did get to handle everything.
    The Duty Grease Gun was the M3 which I remember because of the crank on the side. Likely it had little (but some) use because it was tight and to my ten year old grip, very substantial.
    Not too long after, once the other Cubs had gone home, Dad and I trooped back to the range and I gained a VERY substantial education in long-range shooting with a 1911 and an M3.
    I won’t go into details, but…At a hundred yards…M3 VERY accurate, like a Thompson on sem-auto. 1911…VERY accurate, once you understand it…All VERY heavy, especially to a ten-year old.
    On the way home, Dad said, “it’s probably best not to casual mention what you learned today. Later on, it might become handy…”
    As it turned out, in the ensuing decades, it was…

  3. Excellent and informative presentation about the .45acp caliber M3 and M3a1 SMGs!
    Thanks Ian!

    I really, really like the design of the M3a1. I wish more firearms had the notched bolt for the finger to pull it back… I think the feature is limited to one of the 9mm pistol/9mm “PDW” designs by the Pole engineer in the Forgotten Weapons/ARES British SMG episode recently.

    That said, I think the M1 carbine really might have replaced the entire SMG suite in U.S. inventory and thereby simplify logistics–just make more carbines including a full-auto variant (M2), paratrooper folding stock, and maybe even a shortened carbine barrel with muzzle-brake, etc. I know that’s just not how things work out, however. My understanding is that the U.S. Ordnance officials gave some thought to producing the Sten as a nod to interoperability, a common weapon system for the United Nations fighting the Axis, but rejected the gun as a) using a 9mm cartridge that the U.S. did not use and at the time had no plans to adopt, and b) wasn’t invented here. Seems another missed opportunity… Imagine a Hyde-designed GM produced 9mm SMG… And maybe a better–more reliable–magazine, hmm?
    My understanding is that the Chinese Nationalists, and later the Chinese Communists, produced copies of the grease gun, including in 9mm.

    As for 9mm M3 Grease guns, post-WWII the Argentine military industry produced the pistola ametralladora “PAM” that was simply the same Hyde design by in 9mm. U.S. arms aid in the Cold War saw the M3 and M3a1 widely distributed throughout the so-called Third World. It was the primary SMG that the CIA provided for the AB 2506 during the Bay of Pigs invasion, and also to other counterrevolutionary groups in the Escambray and so on.

    The use of the guide rods with captive springs to avoid contact between the bolt and the stamped receiver strikes me as pretty ingenious.

    • “rejected the gun as a) using a 9mm cartridge that the U.S. did not use and at the time had no plans to adopt”
      But notice that United Defense M42 also called Marlin sub-machine gun was produced in exactly this caliber (9×19), it use magazine of capacity 25 holding 50 rounds, so far I know unique to this weapon. I don’t know – does it can use any other magazine, for example STEN or MP38? As it was delivered to resistance movement it would be handy, but even if no it was better to have 9×19 weapon (so captured ammunition might be used) than .45 Auto.

  4. Something occurs to me from watching that demonstration, how the design details of the M3 allow it to be easily broken down (and easily reassembled) for very compact transport.

    With the magazine and barrel removed, all the pieces fit within a very small maximum dimension. Ah, but then wouldn’t the bolt fall out of the receiver? That’s where that oddball dustcover/safety once again comes into play, because with the dustcover closed the bolt is still contained while the barrel is removed.

    Clearly a lot of thought that went into the engineering of the M3. Perhaps even that goofy single position feed magazine was to allow easy conversion between .45 and 9mm calibers?

  5. My limited experience with the M3A1 was being trained in the Fort Riley Unit Armorer Course during August 1984 on the variety of small arms in the First Infantry Division, the issue of some M3A1 submachine guns to my battalion in the 3rd Armored Division between March 1986 and February 1989, and between October 1994 and July 1999 on an anti-terrorist security officer contract in Kuwait my arms room had 70 Grease Guns and the officers on the contract fam-fired a magazine or two at 25 or 35 meters. In the 3rd Armored Division, my platoon leader carried the M3A1 for a while–bolt removed–because he wasn’t issued a pistol and he found that as a prop for the maneuver areas the Grease Gun sans bolt was shorter and lighter than his issue M16A1 rifle–and that lieutenant left his butt stock and bolt group in his duffle bags until he was forced to put the stock back on by his chain of command. As he carried it only for decoration, I guess it didn’t matter…

    A feature not mentioned in the video is that the M3A1 shoulder stock was also the cleaning rod. It’s possible to screw a bore brush on one of the rods and a slotted jag on the other and use one shoulder stock to clean multiple SMGs. I really liked the magazine loader design and found that it was only necessary after the first 20 rounds were loaded. As a barrel wrench, it worked fine. The oiler bottle in the pistol grip wasn’t used much in the security force role–in fact on that contract other than the personal security detachment (PSD) and one fam-fire session for the entire contingent of security officers, the 70 Grease Guns remained in the arms room getting cleaned monthly (mostly to keep them clear of dust).

    The video contained another error: the 9mm conversion kit, according to reference materials three parts were swapped to convert the M3 and M3A1 to 9mm–the barrel, the magazine and the BOLT. It was a simple operation that the user could do–but I’ve only read of the kit and haven’t seen one.

    I did see a silenced Grease Gun in one or two museums, but can’t remember which museums.

    Despite the crude execution, the design of the M3A1 is elegant from an engineering perspective. There’s little that doesn’t need to be there. Everything required to function as a bullet hose for short-range combat is present. The cleaning gear wasn’t a luxury because some means of punching the bore to remove debris in the barrel is a combat weapon requirement.

    My limited shooting impression was that the Grease Gun put bullets where I wanted them. I worried that the sights might not actually point where the bullets struck and didn’t have enough range time to determine if that was the case, but it worked fine at the short fam-fire distance. I found it very easy to fire single shots (I prefer about 900 rounds per minute cyclic rate in automatic weapons) and the slow cyclic rate also keeps the magazine from running dry rapidly. A cyclic rate of 360 rounds per minute (three hundred sixty) fires 6 bullets per second; a cyclic rate of 600 rounds per minute launches 10 bullets per second; a cyclic rate of 900 is 15 per second and a 1200 rpm cyclic rate will launch 20 bullets per second. Several things will control how many of those bullets will impact a point target. Talent is a factor because some people just cannot master press-release to unleash neat little three-shot bursts (WWII doctrine was longer automatic fire bursts, as many as ten shots launched at a single target–but that changed quite a bit during the war depending upon the army–and the foot soldiers at the tip of the spear often ignored the Holy Writ that the brass sent down the chain of command because the garbled magic rituals sent from on high didn’t fit battlefield realities). The M60 belt-fed machine gun was supposed to be fired in 6 to 9 round bursts…except when it wasn’t. I mentioned rituals–there were exercises to limit bursts to three and six and nine rounds, but these drills were not practiced on the live fire range normally. I ran several machine gun familiarization live fire ranges for the Nevada Army National Guard’s Signal Corps unit from 2003 to 2009 and managed to incorporate the burst control drills on the range–along with practicing alternating fire between pairs of M249 Squad Automatic Weapons. Given the minimum training time, I don’t have high hopes that the drills “took” and would work under combat conditions.

    As for single position feed versus dual position feed, start with “the single most reliable magazine is single column and single position feed up to the point where magazine spring tension causes too much friction.” In English, if you are shooting ten or fewer shots from your magazine, single column is simpler and more reliable. Double column magazines offer shorter magazine length at the cost of a fatter magazine–and spring tension for a twenty shot dual column magazine is comparable to a ten shot single column magazine. Then it becomes complicated. You need a wider feed ramp and receiver to allow dual position feeding than if you had only one feed position. The esteemed Browning High Power pistol of 1935 had a “thirteen shot” magazine that was double column and single feed position. Due to design and manufacturing factors, the user was advised to carry only 12 cartridges in the magazine–and with kiss and a promise field maintenance and other abuse factors, losing one round magazine capacity for increased second and third shot reliability wasn’t a big deal. Fully loading the magazine works as long as you have clean magazines–this is the same for dual position feed (the M16 is dual position feed) and single position feed. Currently the M9 Pistol (Beretta 92 family in 9mm NATO) is double column and single position feed, and as long as grit in the magazine doesn’t prevent the cartridges from rolling during the feeding process, the magazines won’t jam.

    M3 Submachine Gun magazines were provided with rubber or plastic caps to keep that grit out of loaded magazines. I have no clue as to how many of these magazine caps were actually in the field. I didn’t see any and neither did my armorer school instructor–they were in the catalog but were Class IX items and no unit supply sergeant wanted to spend his unit funds procuring them through the supply system! Besides, when kept in the gun or in magazine pockets, most of the mud and dust didn’t get to the magazine interior. This is a case of the real-world logistics system and technical band aids to fix perceived equipment shortfalls colliding.

    The magazine for the M3 submachine gun was modified (I forget how) and used in the Ingram M-10 submachine gun–which had almost three times the cyclic rate of the Grease Gun. The Ingram was lighter and shorter without the muzzle suppressor screwed into place and was marketed as a replacement for the Grease Gun as a local security weapon for armored fighting vehicles.

    Comparing the Grease Gun to another “submachine gun” in the 1984 First Armored Division inventory, the M231 Port Firing weapon, may be instructive. I only read about the M231 and didn’t handle one. The concept was borrowed from West Germany’s Marder and adaptors for their MP2 Uzi submachine gun that permitted firing from behind armor. The major reason it failed in US service was probably the conceit that it was a weapon with 300 meter effective range–but the M231 fired from an open bolt and had the M16’s standard (NATO’s standard) 30 round double column dual feed position magazine. Fifty meters was a more reasonable firing distance given that there were no sights on the port firing weapon when it was plugged into the firing port of the M2 Bradley Infantry Fighting Vehicle–the magazines were loaded with all tracer and after guessing where to point, the gunner adjusted to walk the projectiles on target. The limited mission was preventing infantry from swarming the AFV and detonating satchel charges against the armor, and Bradley IFV’s were expected to delouse Abrams tanks and other Bradley IFV’s in street fighting because the limited fire fan from the gun ports didn’t cover all approach angles to the Bradley.
    The same mission could have been accomplished by “mini Claymore mines” — one time.

    In my opinion the biggest problem with the M3 and M3A1 Grease Gun was tactical doctrine. The US Army never really did like the submachine gun–except for a few special mission units. The Grease Gun could take a suppressed barrel instead of its normal barrel and that might have been quite useful for scouting and raiding patrols–and for some ambushes. It didn’t catch on in the Regular (“real”) Army–only the sneaky Petes routinely carried and used suppressed weapons. It was remarked that the M3’s suppressor wasn’t as quiet as the STEN–I’ve only training videos to go by, and limited firing and observation of suppressor equipped firearms over decades. Firearm suppressors add cost, weight, complexity and increase weapon bulk over firearms without suppressors–and don’t make the gun silent, only reduce and change firing signature. The Ingram M-10 addressed the bulk and weight issues by compact design and its high cyclic rate marked this as an expert’s weapon–the 9mm editions were considerably quieter than 9mm pistols (about as loud as rimfire small bore rifles) and didn’t sound like gunfire. US Army doctrine still doesn’t like placing full auto fire in the hands of every front-line trooper as evidenced by the M16A2 three shot burst position replacing the full auto. Worse, the burst device requires mastering semi-automatic trigger control and until the operations in Iraq there wasn’t adequate instruction in semi-automatic trigger control (press the trigger to the rear until it fires, follow through by holding the trigger to the rear until the sights return to target after recoil, and then relax trigger pressure until the sear resets), let alone drilling in full-auto trigger control (tap the trigger for a short burst, press-release for a longer burst, press for a short count and release for a longer burst). Many units have AirSoft training guns that allow economical and safe practice in trigger control and in various assault fire techniques–but other training priorities take up all of the time. Even so, when the tactical training is emphasized, combat training proves effective on the battlefield. Realistic training also exposes tactical doctrine issues–without losing battles or killing off your own troops.

    The US Army didn’t like the Thompson because it didn’t fit Army tactical dogma–but front line troops appropriated all the Thompsons it could, used enemy weapons such as Germany’s MP-40 when possible, doubled the number of Browning Automatic Rifles in the “rifle squad” even when attrition reduced squad strength from the 12 in the TO&E to as few as 6, and swapped out a number of the excellent M1 Garand Rifles for M1 Carbines or M3 Submachine Guns when street fighting was anticipated.

    The M3A1 Submachine Gun was officially “replaced” by the M-14 Rifle in 1957. The Grease Gun held on because even when the bugs were worked out of the M16 the Grease Gun did things that the M16 couldn’t do. Not that the Grease Gun was an outstanding weapon–Special Forces needed effective submachine guns for some missions and Marine Force Recon used the M3A1 for its early recon teams exclusively due to its “break contact” doctrine. Tankers had small hatches to negotiate and the interior of a tank wasn’t roomy enough to stash four full-sized rifles. Get the best tool for the job. For a long time, the M3A1 was the best tool available for many of the jobs American Soldiers were tasked with: a secondary weapon for local protection of an armored fighting vehicle, room to room combat in large buildings, a personal defense weapon for second-line personnel operating communications systems…

    The US Army had a doctrinal work around for submachine gun superiority in city fighting–don’t fight in cities. Note that at the time the AKM was standard in the Red Army and worked very well in city fighting. AKM versus M3A1–which overall is superior? Where is the Grease Gun superior? Pick the right tool for the job–and remember, if it isn’t in your tool box, it isn’t right for the job because you don’t have it. In 1944 the Grease Gun was the right tool for a number of jobs–though the M1 Carbine was issued in larger numbers (over six million M1 Carbines built versus roughly 600,000 M3 and M3A1 Submachine Guns).

    • I wonder what the US Army tactical doctrinal workaround for SMG superiority in forest fighting was… The US Army was able to mostly avoid forest fighting after the first year of the Pacific campaign in WW2, but even in Central Europe there were and are are quite a few forests. I suppose the relatively late fighting in Ardennes and Hürtgen forests was not sufficient to really teach any major lessons, since the war was close to its end. Armies usually learn lessons much better when they are struggling rather than winning.

      • Euroweasel,

        The US Army workaround for forest fighting was to nuke ’em. When that wasn’t feasible, it was to saturate the area with artillery fire. This backfired in Vietnam because of issues like communications, navigation (where the hell are we?) and especially the “hug the belt” tactics used by the Vietnamese to avoid American artillery fire. This tactic had been perfected against ARVN before mass quantities of Americans arrived and was a feature in the famous Ia Drang November 14, 1965 battle in the movie “We Were Soldiers”–but the Cav was equipped with early M-16 rifles (no forward assist assembly) and not the standard M-14. Those early M-16’s followed the M-14 ammunition basic load example with four or five 20 round magazines (I’m not certain due to lack of documentation) plus a bandolier of 120 rounds to reload the magazines–plus whatever else the NCO’s managed to load on their guys. This was the first big battle where the M-16 was combat tested, and it worked just fine then with the elite Sky Cav troopers. The M-16 may have been the factor that allowed the 7th to survive that battle–if they had carried the WWII weapon mix of M1 rifles and BARs with M1919A4 light machine guns as their “heavy firepower” they may have been overwhelmed. The M-14-equipped rifle platoon was less effective in combat under 50 meters distance than was the old World War Two squad with added submachine guns and “more than its fair share of BARs”–the Marines had three-BAR “rifle squads” and the US Army’s standard rifle squad was one M-14 adopted to fire automatic and the rest locked on semi-automatic only, with a pair of M60 machine guns assigned to the platoon. Look up the 7th Cav’s TO&E of the period to see what the actual mix was–no one single weapon makes an army. It’s a mix of weapons and the doctrine, tactics and training that work.

        In contrast, the Viets had two regiments involved, the 33rd and the 66th–and they got close or they remained in fortifications to survive the American artillery and air power.

        Most of the Viet casualties were due to air strikes–the helicopter gunships delivered fire closer to the American “lines” than anticipated. The Americans were so desperate that they brought in B-52 bomber strikes closer than doctrine allowed.

        Think about how that would have played out in Europe during a Red Army blitz on November 14, 1965. The Viets didn’t have mobile SAM batteries in South Vietnam to counter the B-52. There weren’t large numbers of MiGs to counter close air support in Vietnam, nor air raids on forward American air bases. Ia Drang was almost an isolated battle–in Europe there would have been large numbers of multiple brigade-sized probes across the entire width of Germany. The unit involved would have been on its own because of priorities.

        Ever hear of the Davy Crockett? That was the US Army’s answer to lack of submachine guns and submachine gun doctrine!

        The Battle of Monte Cassino during the Italian Campaign in WWII demonstrated how well the Davy Crockett would have functioned when pressed into city fighting.

        Submachine gun doctrine led to the development of the assault rifle–that’s FIRST World War submachine gun doctrine. The 7x92x33mm Kurz was developed during the pre-war 1930’s in Germany and adopted in 1943–contemporary with the Soviet M43 7.62x39mm cartridge later made famous in the AK-47. Combat experience demonstrated the limits of both service rifle and submachine gun capabilities–and both Soviet and German armies had credible light machine guns in their rifle squads. For a while the Germans contemplated replacing all squad arms with their MP-44, but logistics didn’t permit that. With a little more leisure time, the Soviets simply replaced their WWII DPM with the RPD, their M1891/30 rifle with the SKS, and the one or two PPSh-41 submachine guns with the AK-47–as soon as they could. During the Fifties, the Soviets discovered something amazing–their “submachine gun” was capable of doing everything their carbine was capable of and so the Soviet squads went to RPD and AK exclusively. Then they specialized, swapping out their squad machine gun for a long barrel AK with a bipod and 40 round box or 75 round drum magazines when foot mobility was the priority or a “big bore” 7.62x54mm Rimmed belt fed PK machine gun when firepower was the priority. It helped that the Soviets had battlefield experience with entire battalions carrying nothing more than the PPSh-41 submachine gun.

        Contrast the Davy Crockett to the AKM assault rifle–the US Army work-around for fighting in woods and cities was “don’t!” In Vietnam, the other guys didn’t cooperate and US forces weren’t allowed to use the Davy Crockett.

        • The Davy Crockett has a nasty tendency to splash the user with nuclear radiation if he doesn’t immediately SPRINT AWAY AT THE SPEED OF SOUND just after pulling the trigger.
          From Wikipedia:

          The M-388 would produce an almost instantly lethal radiation dosage (in excess of 10,000 rem, 100 Sv) within 500 feet (150 m), and a probably fatal dose (around 600 rem, 6 Sv) within a quarter mile (400 m).

          Would you really risk NUKING YOUR OWN MEN along with your enemies?

          • I first read about the Davy Crockett when I was in junior high. The source was a coffee table book by Colby and after much “know it all teen age brat” thought I concluded that the Davy Crockett was just a deception operation. There were tests, perhaps deployment of token and dummy units–but the Atomic Hand Grenade wasn’t real.

            I was wrong. While working with the Nevada Army National Guard, part of my range officer certification was decontamination of ranges used for nuclear weapon training–including the Davy Crockett.

            Speed of sound wouldn’t have been enough. Be under cover. Better yet, teleportation!

            Yup! Atomic hand grenade! Wasn’t even that devastating, just dirty–contamination of the battlefield. The Davy Crockett and the Genii air-to-air atomic rocket were the first enhanced radiation weapons in US service–real death rays.

          • The firing range of the M28 ans M29 Davy Crockett launchers were 2km and 4km respectively. The crew was well outside the 400 meter lethal radiation radius and if protocols were followed, behind a barrier or in a trench to avoid direct flash.

        • The declassified _Tactical Nuckear Weapons in Southeast Asia_ report is available here:

          Recall that use of atomic weapons was conidered–and rejected–in Korea, to stave off French defeat at the hands of the Viet Minh at Dien Bien Phu in April-May 1953, against China in the Taiwan Straits crises of 1954 and 1958, Cuba October 1962, and also in Vietnam. In all cases the “nuclear taboo” persisted. See Peter Hayes and Nina Tannenwald, “Nixing Nukes in Vietnam,” _Bulletin of Atomic Scientists_ (May-June, 2003).

          • Bruce Cumings, _The Korean War: A History_ (Modern Library/Random House, 2010), pp.156-58:
            “[U.S. leaders] came closest to [using atomic weapons] in early April 1951–precisely the time that [POTUS] Truman removed MacArthur. It is now clear that Truman did not remove MacArthur simply becaus of his repeated insubordination, but also because he wanted a reliable commander on the scene should Washington decide to use nuclear weapons, that is, Truman traded MacArthur for his atomic policies. On March 10, 1951, MacArthur asked for a ”D’ Day atomic capability’ to retain air superiority in the Korean theater, after intelligence sources suggested the Soviets appeared ready to move air divisions to the vicinity of Korea and put Soviet bombers into air bases in Manchuria … and after the Chinese massed huge new forces near the Korean border. [9x Mark IV bombs to the 9th Bomb Group Guam/Okinawa] … The Joint Chiefs again considered the use of nuclear weapons in June 1951, this time in tactical battlefield circumstances, and there were many more such suggestions as the war continued to 1953 …Operation Hudson Harbor … lone B-29 bombers were lifted from Okinawa in September and October 1951 and sent over North Korea on simulated atomic bombing runs … “

      • That much is obvious. So far as I’m concerned (after lots of reading), the American approach to infantry forest fighting was not to “match automatic weapon for automatic weapon” but to “call the artillery guys and tell them to turn the area into burnt-out and utterly devastated moon-scape.” The concept of not fighting in the cities was likely to avoid civilian casualties, ambushes from the other team, and booby-traps. And sadly for the “almighty hammer of naval gunfire,” Iwo Jima’s defenders were hardly even scratched before the US Marines got on the beach because the Japanese underground bunkers were practically battleship-proof. To add insult to injury, Iwo Jima, which was predicted to be completely captured within hours, took a MONTH to fall.

          • Thank you, Alan. Good to hear from someone who’s “been there and done that”.

            All the talk of “doctrines” reminds of an old joke my one uncle (LTCOL, Army Corps of Engineers, North Africa, Italy and etc. from Torch on) told me about “Unit ID in the desert”. It went;

            If you came upon an infantry unit “up the blue” and couldn’t ID it, the drill was to fire one shot in a safe direction.

            If the response was a volley of precision, timed rifle fire, they were British/Commonwealth.

            If it was a fusillade of machine-gun fire, they were German.

            If they threw grenades first and then laid on MG and rifle fire, they were Italian.

            If they tried to sell you something, it was a local caravan.

            And if nothing happened for five minutes and then your position was obliterated by artillery fire and/or an air strike, they were Americans.

            He also said, “And if nothing happened for two minutes and you felt a tap on your shoulder, they were Ghurkas. Who would be smiling and saluting politely, and returning those big kukris to their sheaths, once they were sure you weren’t Germans or Italians.”

            He nominated the Ghurkas as “the scariest guys in the Western Desert”.



          • Finally, somebody gets it.
            To those that don’t and refuse to read a history book, welcome to the meat grind….No…Let it be a big surprise…

        • Finally, somebody gets it.
          To those that don’t and refuse to read a history book, welcome to the meat grind….No…Let it be a big surprise…

        • “Iwo Jima’s defenders were hardly even scratched before the US Marines got on the beach because the Japanese underground bunkers were practically battleship-proof.”
          If I am not mistaken flame-throwing tanks were found in such environment.

          • Iwo Jima was the debut of the M4A3R3 “Zippo”, which was the first factory made American flamethrower tank. Earlier a field conversion nicknamed M3 Satan or “Ronson” (latter was the Canadian name for the flamethrower unit) was used as well, based of course on the M3 light tank.

    • “US Army never really did like the submachine gun–except for a few special mission units.”
      During World Wars U.S. forces deployed shotguns, calling them Trench Guns (for examples see Winchester Model 1912 for WW1 and Stevens Model 620 for WW2) which full-fill similar role to (early) sub-machine guns giving heavy fire-power over short distance (though without “single bullet” options).
      Default WW1 12 gauge shot-shell contain nine 00 “buckshot” (.34″ diameter)

      • Imperial Germany tried to sue America over the use of trench guns, claiming that shotguns maimed and then left soldiers to die slow, painful, and utterly traumatizing deaths (supposing the victims had their chest cavities blown wide open with lead shot before dying). In essence, the Kaiser Reich equated American shotgun shells to musket balls designed to explode AFTER penetrating the intended victim (a violation of both the St. Petersburg Declaration and the Hague Convention)! However, it seems more likely that German soldiers felt insulted that Americans would wish to kill them with “hunting guns” (shotguns were generally reserved for gentry in Europe, and usually those shotguns were break-action weapons, not pump-action weapons). The US Army rejected the claim, since the Germans were complaining about pure lead shot (which is NOT military grade in America) whereas the Winchester trench guns were always loaded with copper-plated shot (in compliance with the Hague Convention, none of the pellets expand upon impact).

        • “violation of (…) the St. Petersburg Declaration”
          Not. Speaking simply Saint Petersburg Declaration of 1868 prohibit firing of explosive projectiles under 400 grammes by soldiers of one signatory against soldiers of another signatory, which were citing https://en.wikipedia.org/wiki/Saint_Petersburg_Declaration_of_1868
          Austria-Hungary, Bavaria, Belgium, Denmark, France, United Kingdom (representing the British Empire), Greece, Italy, the Netherlands, Portugal, Prussia, the North German Confederation (i.e., Greater Prussia), Russia, Sweden-Norway, Switzerland, the Ottoman Empire, and Württemberg.
          Thus it was illegal for German forces to fire such projectiles against British or French forces, but not against American.

        • Um. My sense is that the Germans equated wounds from shotguns as evidence of non-military weapons from non-uniformed/non-professional armed forces, e.g. “franktireurkrieg.” They shot lots of Belgians for similar reasons, even if they clearly understood that the middle-class “Garde Civique” militia was quite a bit like their Landsturm… The guys who used poison gas first, invented the flame-thrower, and every now and then sank a hospital ship or similar were dissuaded from taking punitive action against American personnel with or without shotguns by threats of reprisals… “Shoot our guys, and we’ll start with yours…”

          There are accounts of German machine gunners in the Meuse Argonne firing every single cartridge that they were supplied with, and then standing up and surrendering. U.S. “Doughboys” often bayoneted them.

    • Speaking of AFV crews and the M3 Grease gun… Apparently tests were undertaken with a Krummelauf-type bent barrel attachment, presumably copied as a “proof of concept” from the German versions captured along with all them scientists and schreibtischtäter after WWII…

  6. Fascinating account of M3 Grease Guns!
    Amazing much US engineers were able to reduce parts-count compared with STEN Gun.

    Ian, have you considered doing a segment on how SMG manufacturing was simplified over the years.

    In a related question: which SMG had the lowest parts-count?

    • The Sten gun is typically cited as having 47 parts. I don’t have Peter Laidell’s Sten Gun book handy, but he goes through the various “Marks” like Mk.I, Mk.I*, Mk.II, Mk.III, Mk.V, etc. and shows the numbers of parts in specific “parts” that drives up the count. The assertion of 47 parts, give or take, is for the Mk.III with the welded sheet metal receiver. I’d think some of the German MP.3008 copies might be even simpler.

      I confess I have something of a fixation on “fewest parts” firearms, and so in Thomas B. Nelson and Hans B. Lockhoven’s _The World’s Submachine Guns [Machine Pistols] Vol. 1 (International Publishers, 1963), 202-203 has an experimental M.A.C. 48-2 9mm SMG prototype with dual triggers for self-loading or full-auto and what appears to be MP40 magazines: “Probably the most interesting feature of this weapon is the fact that it is composed of less than forty components.” It had a reciprocating bolt handle on the left side, again like the MP40.

      Some other prototypes like the Cook, etc. couldn’t have too many parts. The PPS-43 Sudayev and M3a1 couldn’t have very many either.

      • “Some other prototypes like the Cook, etc. couldn’t have too many parts. The PPS-43 Sudayev and M3a1 couldn’t have very many either.”
        Small amount of parts is good, though it don’t necessary mean that weapon is simpler – sometime it is better to have more simpler parts, see for example Repetierpistole M.7 – it has only 28 parts, but of very complicated shapes.

      • “PPS-43 Sudayev”
        It was one of best sub-machine of World War II in terms of cost-effect, but before it adoption there was long and not-straight way:
        it was competing with ППШ-2 by Shpagin.
        Нарком (equivalent of Secretary) of armament – Устинов – liked more Shpagin design. Finally order “Produce Sudayev’s design” was finally signed by Нарком of mortars. When introduced to production it was NOT produced by plants of Наркомат Вооружения (roughly translating Ministry of Armament), but by plants of НКСС (Народный комиссариат станкостроения – Ministry of machine-building), НКСП (Народный комиссариат судостроительной промышленности – Ministry of ship-building industry) and НКПС (Народный комиссариат путей сообщения – Ministry of transport /railroads/)

  7. Alan gave us a multi thousand word article in addition to Ian’s video. Things like this are why I keep reading this site. Thanks everyone.

    PS what’s a Grease Gun go for these days? 15-20k? Way over that 20.94 cost of manufacture.

  8. “While the M3 and M3A1 were replaced in front-line service in 1957, they would remain in military inventory as armament for tank crews and truck drivers until 1992 – quite the legacy for such a crude looking weapon!”

    We still had M3A1’s in the Army in Korea in 1996, in the 2nd Engineers (Combat Heavy), 2nd Inf. Div. They were issued to crewmen on the M48 Chassis AVLB (Armored Vehicle Launched Bridge), ACE (Armored Combat Earthmover) and the M60 CEV’s (Combat Engineer Vehicle). The rest of the Battalion (Combat Engineers and Support Troops) had M16A2 or M9 Beretta for individual weapons, plus all the crew served.

    The funny thing is we had them, they were issued for every alert and field exercise, but we did not have a single round of 45ACP in our ammo supply point…………

    • Andrew Luder pointed out that in Korea during 1996 there was no ammo for his unit’s M3A1 submachine guns. In Kuwait the supply of .45 ACP was low, I remember something like 200 rounds for 70 submachine guns. No spare magazines, either–just one per M3A1.

      This wouldn’t be the first time that obsolete weapons were on inventory without any ammunition. I read that US Navy ships during World War Two had really old Krags in their ships arms lockers. As late as the Sixties some of the old ships in service had Springfields and even old Reisings. The Coast Guard was armed with Garands as late as 1986 while fighting the War on Drugs and Ronald Reagan ordered that the Coast Guard was the first to rearmed with the M16A2 rifle and M9 pistol. Now the Coast Guard carries a Sig pistol in .40 S&W. At the end of the world even American logistics has limits. Besides, the M3A1 was low priority and basically forgotten in the 1990’s.

      Changing weapons requires a lot of things be changed–rifle racks on the vehicles, ammunition supplies, web gear–and people have to be trained.

      Andrew, how much training did you get with the M3A1 other than wearing it for decoration?

        • The Coast Guard is not part of the Navy although it has come under the operational control of the Navy at various times.

          The Coast Guard and it’s various ancestors (Revenue Cutter Service, etc.) have bounced around over their history, belonging to agencies including (I believe) the Department of Transportation and the Treasury Department.

          While never having served in the Coast Guard, I was on the Cleveland Coast Guard Pistol Team in the Cuyahoga County Pistol League during the late ’80 and or early ’90s. They were perpetually short of competitors (especially during the First Gulf War) and allowed government employees and contractors to shoot on their team.

      • “Changing weapons requires a lot of things be changed–rifle racks on the vehicles, ammunition supplies, web gear–and people have to be trained.”
        So changing weapon system is done as seldom as possible, which is also true for ammunition. Most cartridges used by major military powers were developed at least 50 years (half of century) ago, often more.

        For example .50 BMG (so far I know still used by U.S.Navy – if I am wrong correct me) was designed shortly after WW1, so in near future it would turn 100th “birthday”.

        Russian 7.62x54R was adopted firstly in 1891 and with Spitzer bullet in 1908 (though unlike German counter-part “round-nose” and Spitzer 7.62x54R are interchangeable) so it has 125th “birthday” yesteryear.

        NATO 7.62×51 is relatively young, but itself is upgraded .300 Savage (produced since 1920) and ballistic-wise near copy of 7.65 Argentine Mauser (which was created in 19th century)

        World-wide popular 9×19 Parabellum was created in 1902.

      • Absolutely none other than stripping it down and cleaning it. But it was a nice small weapon to carry, I think it would have been very handy with some ammo.

  9. George Hyde was also the designer of the short lived M2 SMG. He designed and got the the M3 adopted before Marlin was able to start manufacturing of the M2. Hyde submitted a lot of SMG designs to the US ordnance before getting these 2 adopted.
    A little precision on the M1 and M1A1, it was Savage that proposed simplifications and improved the manufacturing process of the Thompson. Much like Remington did on the Springfield 1903.

  10. I was in the 4th ID 4th Brigade Headquarters Company in Wiesbaden. We had a Tracked Recovery Vehicle and the driver’s issued weapon was a grease gun. When we were in the field I would give him my M16 and take his grease gun when I drove the 1st Sgt around. I felt like such a bad ass. That would have been 1979.

  11. The 9mm M3A1 conversion kits I had contained the barrel and bolt plus a Sten mag and small sheet metal adapter to hold the slightly smaller mag in the mag well. The barrel was set back in the flange a bit to go along with a slightly different bolt face. It fired very well.

    The UD42 mags look just like shrunken Thompson mags and I often wondered if hey also worked with the 9mm Thompson prototypes. Then there were the double UD42 mags which were simply two regular mags spot welded together.

  12. I today visited the Patton museum in Ettelbruck in Luxemburg and wished I had made a picture of a M3A1 there, because I would swear it had a stengun like slot in the receiver with a charging handle in that slot.

  13. I got to fire an M3A1 when I was in Korea in ’80-’81. They were issued to the M578 recovery vehicle crews.

    They are indeed very controllable with their unusually low cyclic rate. I imagine that Jerry Miculek can fire an N frame S&W revolver substantially more quickly, albeit not for very long. The misfeeds which I encountered were directly attributable to a bad magazine.

  14. I recently saw one in a local museum, it was a long barrel variant with a muzzle break and it has a bloody history behind it..

    and the museum labeled it wrong, it was written as a M1 Thompson SMG.

  15. From 1969-1971, two years I carried a M3A1 all the time in Vietnam, I had two, one with the normal barrel and the other with an Ithica “silencer” as they were called in those days. The one with the silencer was nicer to shoot but not good to hump, so I usually carried it only when picking up POWs from the various MAT teams in Quang Tien Province by Huey! Got both from my Viets after I found the M1928 Thompson’s were junk, magazines all bad and failed to feed and fire all the time. Had a home made VC mag carrier which carried 9 x 30 round mags with one in the weapon it made 300 rounds, more than enough rounds under most circumstances. Had to fire it more tha a few times during those 2 years and it NEVER failed to FEED and FIRE, no matter if wet, dirty, muddy, rusty, etc.! It was 100% dependable and I found that firing 4 round bursts, I could fire accurately up to 200 yards, i.e., from tree line to tree line across most rice paddies. Yes far more reliable than the M-16s which were being used at that time!

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