So, a few months back, I wrote some posts on the selection of small arms:
The Right Weapon for the Job
Getting Down to Specifics
In comments the original posts, some folks took exception to my support of the Sub-Machine Gun (SMG); instead of the current general issue of the M4 assault carbine (it is definitely not a full assault rifle, with barrels from 10.5" to 14.5"). Recently, these same objections have been raised agian in a different context.
The objection of these folks, is that the assault rifle does everything the SMG does, only better; and therefore the SMG is obsolete.
Respectfully, I disagree.
I believe this premise stems from a mis-understanding of the proper role of the SMG, the assault rifle; and the transitional weapon between them, the assault carbine.
I think there is a very clear transitional element to subguns, that can be seen when the effective combat envelope of various personal arms are broken down by effective range:
Pistol 0-25m - 10m point blank
Shotgun 0-25m - 10m point blank
SMG 0-100m - 50m point blank
Assault rifle - 25-300m - 100m point blank
Battle rifle - 50-800m -300m point blank
Given this breakdown, it is clear that the SMG sits as a step up between pistols, and full rifles. Now the curveball comes when you add in the assault carbine (such as the M4) which has a rifle chambering, but SMG barrel length.
Assault Carbine 0-200m - 50-100m point blank
(please note that I use point blank in the tactical sense here; as the maximum range at which given the worst normal conditions aimed fire will produce a lethal zone hit, without sight adjustment or compensating fexcessively for bullet drop etc...or
The assault carbine is an attempt to compromise between an assault rifle and an SMG. It does long range a bit better than an SMG, short range a bit worse, and it can’t reach out to the full rifles range. The advantage of course is that you do get some extra range, and that the operating system, parts, and ammunition are all interchangeable with the assault rifle.
The assault carbine CAN replace the role of the SMG (which I cover in my posts), but I personally believe the SMG does a better job of it in many circumstances.
I’ve used both, and I believe the Assault Carbine overall, is an inadeqaute compromise. It isn’t well suited for the longer range it has over the SMG, and it isn’t as small, handy, or easily controllable in the shorter ranged environment.
I believe that the vast majority of combat troops would be better served with a full assault rifle; while those that don't need the assault rifle, also don’t need the assault carbine (at least not over and above what the SMG can do).
This is highlighted when you look at dimensions. The SMG is much shorter and usually lighter than even the assault carbine (the m4 with the 14.5” barrel, and collapsed stock is 29.5”, and weighs over 7lbs unloaded with no accessories. The 8.5” barreled mp5 is 27” with the stock EXTENDED, and it weighs 5lbs) vs. the actual assault rifle.
If I had a mission that involved close quarters battle, with ranges expected in the 0-50m realm, and not to exceed 100m, I would unhesitatingly take and MP5-10 (the 10mm version of the MP5) or a UMP in .45 super, over an M4 (the standard 9mm is still good, but I'd rather have the extra power if available). If I had a high probability of ranges over 100m, I would almost certainly pick a full assault rifle rather than an assault carbine. The only real area where the assault carbine fits, is in that 50-100m overlap.
If my primary mission was in a commo center somewhere, or sitting in the back of a van; I would certainly want more than my sidearm; but dealing with a full sized rifle, or even an assault carbine, would be difficult. I’d be much more like to have an MP5K with me at all times, than an M4; and the SMG is going to be far more effective than jsut a pistol.
Also, the SMG is well suited to police work; giving officers more power, range, and precision than their pistols, without the difficulty in handling in and out of a car and in tight urban space of a carbine or shotgun (and with less overpentration risk, though vs 5.56 it's a tossup)
Additionally, and very important to many operational functions (especially special operations), an SMG is very easily suppressed. Subsonic intermediate rifle cartirdges are very much not easy to suppress. THose loads that are subsonic, generally perform so poorly as to be irrelant, and many wont function proplery with a weapon in field conditions. Even if a reliable round can be found, the cans required for effective suppression with these marignally effective loads are large and unwieldy.
All of this of course presumes you have an SMG that is as accurate at 100m as your assault rifle is at 300m; that is controllable in 3shot burst mode; and that you chamber it appropriately. The MP5 is the canonical example of this.
Personally I’m a fan of 10mm and .45 super for SMGs, in both cases because you have a powerful base round, with good subsonic download options; but even with base 9mm, you get a lot more out of the 8.5-12.5 SMG barrels, than you do from a 4-5" pistol; and of course you have the burst option.
All this says to me the SMG is by no means obsolete. Though I concede that the assault carbine can do MUCH of the SMGs work; it is not ideally suited to the task, nor is it adequate as a full assault rifle.
Now, I do understand the current situation with the near wholesale adoption of the M4 assault carbine as a general issue weapon for the U.S. army means that they are training everyone on the same ballistics ergonomics, manual of arms etc... as the full M16 rifle; and these are defintely large advantages in logistics and training.
The thing is, I believe this is a mistake; at least with the current chambering and barrel length of the M4.
As it is, the M4 is still too long to be better than an SMG for room to room; the extreme lightening of the front end of the rifle makes it even more difficult to control in full auto; it makes even more noise and flash; and in barrel lengths under 18", and especially under 16" (the issue M4 today has a 14.5" barrel), the ballistics of the 5.56 round are severely compromised, effectively limiting the maximum effective range under many circumstances to 100m or so.
Within this 100m envelope, a shorter, lighter, faster handling, and easier to control SMG, with a relatively long barrel for a pistol round (10.5" say), good iron sights, a good optical sight, a decent stock; and in a chambering which can use that whole barrel length; can be as or more effective than the 5.56 weapon, and still be better to use house to house (especially suppressed).
Again, I reference the MP5, especially the -10 variant in 10mm, and the UMP in .45 super (though H&K lists it as a .45acp; it is actually rated for .45 super. I have fired them with the super ammo, and they handle it very well) as strong candidates here.
Even the ergonomic and logistic questions can be addressed. The entire HK lineup share similar feel, ergonomics, operating system, and manual of arms; from the USP pistol, all the way up to the G3 rifle, and it's LMG variants. There is even a significant degree of parts interchangeability in some cases.
So, the SMG is definitely not dead, nor is it obsolete, so long as one understands its proper roles; as the personal weapon for those whoi wokr in tight spaces; in clearing buildings and tight spaces; and in special operations.
Oh, and they're just pretty fun to make brass with too.