Machine Gun Terminology Part 2: SMG, PDW, & Machine Pistol

Today we have Part 2 of machine gun terminology – the small caliber guns. Specifically, submachine guns, personal defense weapons, and machine pistols.

Submachine Gun: Pistol caliber, fully automatic, and fitted with a shoulder stock. For example, Thompson, MP40, MAS-38.

Machine pistol: Handgun form factor and fully automatic. For example, Glock 18, Mauser Schnellfeuer, Stechkin.

Automatic Rifle: Shoulder or hip fired, limited magazine capacity, minimal sustained fire capacity. Examples: M1918 BAR, Chauchat.

Persinal Defense Weapon: (1) Armor-piercing or (2) holsterable submachine gun, not intended for front line combat. For example, FN P90, H&K MP7, Czech vz.61 Skorpion, Polish PM63 Rak.


  1. Which is worse to face in a dark alley brawl, the dedicated personal defense weapon with special ammunition or a machine pistol?

    • The PDW, hands down. Most PDW rounds are considered at least semi-armor piercing, which is another way of saying “barrier-defeating”.

      In plain English, a dumpster will probably stop most pistol rounds up to 9 x 19mm or even .357. It will probably not stop milspec 5.7 x 28 FN or 4.6 x 30mm HK.

      Cover vs Concealment; never confuse the two. And always be aware that what constitutes “cover” is defined by whatever the other guy is shooting at you with.



    • Ppsh, with an adapted 43 magwell for stick mags. Target, 1200 rpm 7.62x25mm bekow the belt, most will hit; Rambo is dead, unless very quickly fixed in the repair shop.

  2. One more modern example of a pistol-caliber PDW than the vz.61 or PM63 might be the B&T MP9/TP9 in any of its versions with the little folding stock and flush magazine for holster carry.

      • “Machinizing” of various automatic pistols was attempted several time in history. It most often ended in smaller or bigger failure. Most automatic pistols are designed without caring about cyclic Rate-of-Fire, which is no problem as they are anyway self-loading, but when modified to full-auto in result in high Rate-of-Fire which mean:
        1) first depletion of magazine
        2) problems with controllability
        these might be solved, although need further altering of weapon and result might not be great. It might be easier to start from scratch.

        One of Russian weapons, which might be called PDW (in Russian anyway classified as sub-machine gun) is ОЦ-22 Бук:
        it is blow-back operated and has following tactical-technical characteristics:
        Cartridge: 9×19 mm
        Mass, unloaded: 1,4 kg
        Length (stock collapsed/extended): 250 mm / 460 mm
        Length, barrel: 119 mm
        Rate-of-Fire: 800-900 rpm
        Magazine capacity: 20 or 30
        Sights scaled to: 100 m

        • What about the APS aka Stechkin pistol, which was designed as a machine pistol almost from the beginning? How controllable is it in full auto without the shoulder stock?

          Another question about the APS: was the official doctrine of the Red Army to fire full or semi-auto if there was no opportunity to attach the shoulder stock?

          • Based on Наставление по стрелковому делу 9-мм Автоматический пистолет Стечкина (апс) available here in scanned form here:

            111. Single and group targets up to 200 m smite with single or full auto fire depending on situation
            112. Group targets smite with full auto fire with changing point-of-aim between particular targets
            113. When defending against attacking enemy or appearing of group target 100 m or more near, fire full auto spraying
            114. In forest fire from behind trees using them as cover and rest. In trenches and other confined spaces fire full auto at point-blank, if holster-stock is attached fire without resting it into shoulder.

            115. Most targets appears for short time, observation and fast executing of operations like attaining position, loading, reloading and so on are crucial
            116. For targets moving in plane of firing (to or from shooter) is done with sight “200”
            117. For targets moving perpendicular to plane of firing use sight “200” and apply following corrections:
            Range, Value for target moving @ 3 m/s
            25 m, 24 cm (1/2 of one man width)
            50 m, 48 cm (1)
            100 m, 99 cm (2)
            200 m, 216 cm (4 1/2)
            [Data are for running targets]
            * use half of these for targets moving by foot-slogging
            ** use half of these for targets moving at acute angle to plane of fire
            *** apply to center of target

            118. Use sight 200, advance as follow:
            Distance, advance in term o parachutist figure
            25 m, 1/2
            50 m, 1/2
            100 m, 1 1/2
            200 m, 3
            [Data for descend velocity: 6 m/s]
            * apply to center of figure of parachutist
            119. Choose stance depending on environment, it must provide stability on fire, if possible rest weapon against something, for example fence.

            120. If target is artificially lightened use rules of daylight fire
            121. Look at where target will appear, do not look at light source
            122. If there is no possibility of lightening target fire in direction on enemy, aim at source of shot sound.

            123. Particularities of firing using gas-mask:
            – glasses become wet from breathing
            – somewhat limited breathing
            effective firing require regular training.
            Wear gas-mask so line-of-sight is perpendicular to glass of gas-mask.

  3. “Persinal Defense Weapon”
    Such term is absent in official Russian terminology, sub-machine gun and machine pistol are differed by presence of absence of shoulder stock or front grip.
    ГОСТ 28653-90 Оружие стрелковое. Термины и определения defines sub-machine vaguely:
    Пистолет-пулемёт — Автомат, в конструкции которого предусмотрена стрельба пистолетными патронами
    That is avtomat, in construction of firing pistol cartridge was anticipated, Wikipedia query has discourse about that.
    Alternative way to differ between sub-machine gun and machine pistol is that for first full-auto fire is default and single secondary.

  4. I believe this PDW moniker was invented as an artificial term by military establishments in cooperation with manufacturers to justify new acquisitions. It does not define any new category, in my view anyway.

    • Strictly speaking, the first “Personal Defense Weapon” was the U.S. M1 Carbine, circa 1940-41. Its original mission was defined in the 1939 RfP as being “a replacement for submachine gun, pistol and some shotguns” in the hands of second-line and support troops, who Edwin Tunis (Weapons, 1954) defined as “soldiers whose main job does not involve shooting, but who sometimes need a gun and need it bad”.

      Tunis also defined the Carbine as “the pistol that looks like a rifle”, in view of its cartridge’s lesser power compared to the old .30-06 M1 “Thunderstick”, but having a lot more “zing” than any pistol-caliber round. Any shoulder-fired arm is easier to hit with than a pistol, especially in the hands of a non-specialist in the latter. And the Carbine had enough range and firepower to give somebody stuck in an ambush or etc. the ability to give at least as good as he got out to 150-200 yards; at which range the .30 caliber pistol-type bullet had more energy than .45 or 9mm slug from a pistol or SMG at the muzzle.

      Tunis also pointed out that the Carbine, in regular and especially folding-stock persuasions, became popular with paratroops because it had more effective range than an SMG, weighed less, its ammo was lighter (so more could be carried on the drop), and best of all, they could “land shooting instead of waiting for a rifle to come down on the next elevator”. (I.e. in a drop container, the standard method until the drop scabbard was developed in 1943.)

      The Carbine was also considered about the best weapon in the Allied inventory for resistance groups, in that (again) it was lightweight, compact, its ammunition was equally so, and it had enough range and firepower to allow guerrillas to slug it out with enemy troops armed with Mauser or etc. rifles if need be.

      Postwar, the Carbine became a favored police weapon here and abroad because it had better range and accuracy than an SMG, did not have the overpenetration dangers of a “full-caliber” rifle, and also in the last four decades its wooden stock and blued steel had a more benign image than an SMG or “black rifle”. (The Ruger Mini-14 became a favored police longarm in the Seventies for roughly the same reasons.)

      In other words, the M1 Carbine was the first “purpose-designed” PDW in any army in the world. It became first an iconic paratrooper arm, and then a ubiquitous arm for everybody from police to “indigenous troops”, because there was nothing else that was really comparable t it for such purposes.



      • I think the artillery Luger was dadopted for roughly the same role and predates the M1 carbine by 25 years. While it uses 9×19, one could argue that for PDW purposes and ranges, in times when Body Armor wasn’t a factor, 9mm is plenty powerful.
        And while the Lange Pistole P08 isn’t full auto, compared to the bolt actions of the day, it enjoys a clear advanteage in volume.

          • Never adopted though.
            Timing also got in the way a bit, adopted in 1913 the long P08 never really got to all those support troops it was supposed to equip, because they were, well, support troops and therefore 2nd in line to get shiny new small arms.

  5. “Machine Carbine” is a WWII-era British Army term for what anyone else would call a sub-machine gun. They disliked the usual name, apparently because it evoked the likes of Al Capone.

  6. Are Americans allowed by law to own sub machine guns? Up in Canada these weapons are considered prohibitive, for which we must be the proper type of Canadian Soldier to possess . I can’t recall an American mass shooting of late in which the shooter was armed with a sub machine gun, so perhaps it is the same in the US as in Canada on that issue. I AM rather surprised that hunters are not allowed to kill wildlife with machine guns, though. They would be able to annihilate far more species so much faster than they do now. In Canada, we preserve wildlife. B.C. has just protected Grizzly bears from trophy hunters.

    • They’re legal to possess in most jurisdictions with the proper paperwork, but due to the limited number available for private purchase they’re very expensive. You’re as likely to see one used for illegal purposes as you are a high end sports car used as a getaway vehicle in a bank robbery. As for the nut jobs, people with the money to buy and keep automatic weapons have better ways to deal with their mental problems than mass shootings.

      • Thanks for clearing that up, John. I notice that you explain that “nut jobs” and “people with the money to buy automatic weapons” are mutually exclusive groups and they have better ways to deal with their mental problems.” Perhaps you might enlighten the police about these “better ways”, since they don’t seem to have heard of them yet. Sounds like a good idea , however.

        • “Better ways” include voluntary psychological counseling to deal with unusual mental stress. Most mass shooters went morally (if not legally) insane and would certainly refuse to admit they had problems in their heads. Anyone who has the money to get true automatic weapons (not jury-rigged bump-fire stocks or garage-mashups) will certainly not go out on mass shootings because they have too much to lose by doing so! And it appears a corrupt “good old boy” network wants to keep regular cops in the dark about mental health problems in order to keep the boys and girls in line. “There are only two types of people in this city: Good and bad. If they’re not good, they’re bad. We shoot bad guys. Deal with it.” Most police around older cities seem to have this problem. Trust me! They usually fall in line with politicians and would certainly not trust a gun smith’s opinion on gun-related evidence, even if it was proven that a handgun presented as “murder weapon, Exhibit A” was actually an antique stolen from a house across town and also incapable of dealing the finishing blow to the victim by reason of ammunition incompatibility! 38 caliber is NOT always 38 caliber, for 38 Special is NOT the same as 38 Super Auto which is clearly NOT .380 ACP.

          Did I mess up the stereotypical problems?

          • The problem with people with mental health problems is that there is virtually no correlation between serious mental health issues, such as schizophrenia or bipolar syndrome, and violent behavior. People with less serious problems are either indistinguishable in ordinary life or the disease effectively prevents overtly violent behavior, as with people suffering from serious depression.

          • I would like to say “I trust” Cherndog as he asks us to. I also agree with Euroweasel that most mental problems are non violent so, the only thing we have to fear is Wackos who do not appear mentally ill , but who really are planning a mass shooting for personal reasons. I wonder if our great leader in the white house knows how to recognize one of those type of mental cases? He should watch his back. Especially in his own house .

      • After a quick perusal of this act (1934),it appears that machine guns are legal in the continental US as long as the tax is paid on it.

  7. PDW seems to be more a description of intent than of hardware. I was expecting someone else to recall the classic quote about side arms:
    ‘You’ll never need it…but when you do, you’ll need it BAD!

  8. Where does the Czech ZB-47 SMG fit in your nomenclature?
    It fires pistol ammo, has a telescoping metal stock and is easier to conceal because its magazine lays parallel to the barrel.

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