Telling the difference between a machine pistol and a compact SMG
 

The following is an article I was writing up for the "General Information" section of IMFDB. It was written to clear up any confusion regarding whether a firearm using pistol-caliber cartridges is a pistol-caliber carbine, or a machine pistol, or an SMG. I would like to hear the community's feedback on it.

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How to tell the difference between a machine pistol, a pistol-caliber carbine, and a submachine gun.

There can be some confusion regarding just where the differences between these three firearm types chambered for pistol cartridges lies. This article was written to help IMFDB's users with that problem.

The iconic machine pistol is a handgun with select-fire capability, or else a handgun capable of fully-automatic fire. And the handgun classification is defined partially by its ergonomics; it has no dedicated place to put your offhand in a different place than your trigger hand, and has no buttstock whatsoever. A true submachine gun, however, has ''both'' a buttstock and a dedicated place to put your non-trigger hand (whether this a sufficiently-long handguard, a foregrip, a protruding magazine well, etc.), as well as select-fire or fully-automatic fire capability. With the exception of the [[Izhmash PP-19 Bizon]] (largely because you don't really have a choice in the matter given how the helical magazine blocks the handguard from below and you shouldn't put your hand in a place that blocks the iron sights), a firearm's magazine doesn't count as a dedicated place to put your off hand, since that will likely cause a malfunction. Both these features, along with select-fire or fully-automatic fire capability, are necessary for a firearm chambered for handgun cartridges to be considered a true submachine gun.

Examples

• A Beretta CX4 Storm has both a buttstock and a sufficiently-long handguard to put your off hand, but is limited to semiautomatic fire only. It is thus a pistol-caliber carbine. The recently released MX4 variant, however, does have select-fire capability, making it a true submachine gun.
• A standard MAC-10 does have a buttstock and fully-automatic fire capability, but no dedicated place to put your off hand (the space between the pistol grip and the muzzle is distinctly undersized for this purpose). It is therefore a machine pistol, albeit with a buttstock. For the same reason, the Sa. Vz.61 Skorpion falls into this category.
• The original Steyr TMP has select-fire capability and a foregrip, but no buttstock. Thus, it is still a machine pistol, just with a foregrip (though the more recent variant, the Brügger & Thomet MP-9 with its folding buttstock, is an actual submachine gun). The Beretta M93R is also in this category for the same reason.
• A full-size stock Uzi counts as an SMG because of its buttstock, select-fire capability, and the cylindrical protrusion (from in front of the trigger to just before the muzzle) IMI put there as a place for the user's offhand.

Grey Areas

• A machine pistol like the [[Glock 18]] could conceivably be converted to a compact submachine gun by using the CAA Tactical RONI-G1 conversion kit, but because it wasn't originally manufactured as a submachine gun, it's still only a machine pistol in a conversion frame.
• A pistol-caliber carbine's barrel length, unlike the other uses of the term "carbine" which normally means "shorter than full size," is actually longer than usual "handgun-length" barrels. "Handgun-length" (in terms of barrel length) is conventionally 6 inches or less, the reason being that a longer barrel length would make the pistol difficult to holster or draw.

Really I don't think That you can really distinguish between Machine Pistols and Submachine guns.
The way I see it is that a Machine Pistol is a subcategory of submachineguns.

To put it bluntly

All Machine Pistols are submachine guns...But not all submachineguns are Machine Pistols

Pistol caliber carbines are usually somewhere around rifle-sized. Most (but not all) that I can think of are semi-automatic as well

I don't really see any difference between machine pistol and submachine gun

I wrote this guide originally as a response to users like the one who incorrectly moved the Cobray M11/9 to the submachine gun section of the Max Payne (video game) page, which I provided the vast majority of screenshots for.

As I outlined above, the crux of difference between a machine pistol and an SMG is their ergonomics, though their select-fire/fully-automatic fire capabilities and caliber types are the same. A Machine Pistol has the ergonomics of a handgun or not all the ergonomics of a rifle, an SMG has (or should have) all the ergonomics of a rifle. And weren't SMGs invented and used before Machine Pistols were?

Currently, the wiki doesn't lump the Machine Pistol and Submachine Gun categories together, so I wrote this guide to be posted on the SMG and Machine Pistol category talk pages to let users immediately tell the difference and categorize the firearms within correctly.

That's the funny thing. Pistol-caliber carbines have the carbine designation because their barrels are longer than standard full-sized pistols (normally above six inches, since six inches is the maximum "practical" pistol barrel length). In all but this case the term "carbine" refers to a firearm with a shorter barrel than a standard full-sized firearm of that caliber (battle rifle, assault rifle, etc.). This exception should be more widely known amongst the wiki's users.

Well going by the dictionary definition an smg is just a machinegun that fires pistol type rounds.

http://www.merriam-webster.com/dicti...bmachine%20gun

Unless the wiki is going to lump the machine pistol and SMG categories together, I believe a definition like mine would do well to settle the grey areas between the two. And the "machine gun" definition is a bit outdated by those unfamiliar with firearms. It used to mean any firearm that was capable of fully-automatic fire or was select-fire. Now that term should stick with the infantry support weapon class or a vehicle-mounted fully-automatic firing weapon.

I don't think that's the case. The term machine gun has simply evolved to have two meanings.

And one of them has sadly been over-inflated and given negative connotations. I much prefer the more accurate term "fully-automatic firing weapon" because any slug-throwing weapon can be made to fire in a fully-automatic fashion, but not every fully-automatic weapon can fill the role of a Light/Medium/Heavy machine gun.

If there are no more forthcoming objections, I believe I'll be posting this guide to the SMG and Machine Pistol talk pages soon.

Personally I think this guide is kind of arbitrary imho

Pardon me, where was I being arbitrary? I thought I clearly explained my reasoning.

Your creating a definition for a submachine gun that goes further then the dictionary meaning, or then what most people would consider a smg. That is arbitrary.

I based it on the fact that the archetypal machine pistol is a handgun converted for select-fire and/or fully-automatic fire capability. That is what separates a machine pistol from other types of handguns--the ergonomics could be exactly the same (i.e., such as when you compare a Glock 18 to a Glock 17) as a similar semiautomatic-only handgun, but select-fire and/or fully-automatic fire capability would be what separate the two.

Firstly, this is in the wrong section, it should be in the IMFDB subforum.

Second, where are you getting these definitions from?

Pardon me, I was under the impression that since it dealt with guns and how they should be categorized it belonged in this forum. If it should be moved to the imfdb subforum, I have no objection.

And I did not get these definitions from anyone/anywhere else. I figured them out on my own. Again, all that separates a handgun from a machine pistol of the exact same outward appearance is either select-fire ability or fully automatic fire capability (if that is the only fire mode available).

The Bergmann MP18, being the first "true" SMG, had the ergonomics of a rifle, fully-automatic fire capability, along with a buttstock and a dedicated place for your offhand (the "mission profile" when they were first created was to create a light, compact, but accurate weapon you could shoulder and steady with both hands to fire in the confines of WWI trenches, after all). Without one or both of those ergonomic devices (such as when H&K made the stockless MP5K), a former SMG becomes much harder to aim and fire accurately (a stockless MP5K weighs more than a Glock 18 and with no buttstock is much harder to keep on target for anything other than semiautomatic fire), and thus would be closer to a handgun than a rifle in the ergonomics department.

Conversely, sticking just a stock on a Glock 18 doesn't make it a submachine gun anymore than a M712 Schnellfeur with its holster-stock fitted on it makes it a submachine gun. It's still a machine pistol with a stock, because there's no dedicated place to put your offhand (you could try holding down the stock in the case of the Schnellfeur while firing a burst, but the leverage is working against you). Sticking a Glock 18 in a FAB Defense K.P.O.S. conversion kit would, however, give you an ersatz compact SMG because of the stock and foregrip included in the kit. I say "ersatz" because that's not what a Glock 18 was purpose-made for, and one in such a kit may have the ergonomics of a rifle/SMG, but at its core it's still a machine pistol.