Thursday, June 09, 2011

Pistol-caliber vs. rifle-caliber carbines

Been thinking about this since I read Tam's review of shooting the KRISS guns, in particular this part:
There's only one problem: Most of the people who used machine pistols have gone to rifle-caliber "shorty" carbines over the last few years; any agency still using the MP5 is probably going to replace them with M4s or shorty G36's or the like, rather than another pistol-caliber weapon.
My question is 'Why?' I understand a rifle cartridge has more power, but- with everything being a tradeoff- what's the big advantage for a LE organization switching something like a tactical team from a subgun to something like a very short-barreled M4?

Yeah, a .223 is more powerful than a 9mm or .40S&W or .45acp or 10mm; enough so to make up for the increased muzzle blast(for one thing)? I haven't seen a M4 firing up close with a 14" barrel, I have seen a couple of AR15 pistols fired indoors, and the blast and- with some ammo- flash was fairly awful; I can't imagine a M4 with a shorter barrel(don't they make variants with 10" or 10.5" barrels?) would be much better.

I have no personal knowledge to make a statement from, I'm just wondering here.

By the way, just out of curiosity I looked at the Colt site: in their 'law enforcement' and 'M4' section it says
Colt M4 Carbine is the weapon of choice according to today's law enforcement concepts of rapid deployment, mobility and increased firepower. etc. Then, down below,
- M203 40mm Grenade Launcher mounts directly to the Carbine without modification
Hmmm. Is that generally a selling point for LE?


Sean D Sorrentino said...

I wish I knew the answer to that one as well. How exactly do you go about finding out? The sort of people who run about shooting enough people to have a basis for comparison between the two weapons are notoriously closed mouthed.

Until I shot the Kriss, I was all fired up for a supressed 10.5" Noveske. Now I want the Kriss with a suppressor.

Am I really going to get enough range out of the 10.5" 5.56 that would justify changing my mind back? And where exactly in my civilian life would I need to shoot at anyone beyond 50 yards? The bullet from a +P loading leaves the barrel at a little less than 900 fps and at 100 yards will still be doing over 800 fps.

Plus, I already reload .45ACP.

Sigivald said...

Well, the for the M203, the ability to fire tear-gas (or OC) grenades is a real LE draw.

(For the "LA Riots Part 2" sort of scenario, say.)

I suspect the preference for rifle calibers also harkens back to overreaction to The North Hollywood Shootout.

(And also, sadly, a desire to be Just Like Soldiers; but there are plausible, if overreactive, actual-law-enforcement reasons for it as well, as above.

Hmmm. Does everything bad come from LA? Possibly!)

Anonymous said...

In the pre body armour six day war, Israelis armed with Uzis cleaned the Syrian's trenches on the Golan, of their AK armed defenders.

In that conflict, rapid handling of the theoretically slower, open bolt pistol calibre gun trumped the theoretically faster and more powerful AK.

Again, pre body armour, experience in the Spanish Civil War, showed that powerful rounds like the 9 x 25mm mauser export (hotter than .357 Mag) and the 9mm largo had no practical advantage over 9mm P.

I guess that the bureaucrats sending ninja suited thugs to kick down tax payer's doors want to blow the those same tax payer's hard earned on something which looks exciting.

I was looking through a friend's copy of Cartridges of the World, it's a lot newer than mine, and listed whisper loadings of .30 luger and .30 mauser/tok pistol cases by JD Jones with muzzle energies of 600 to 700 foot pounds out of 7" and 8 3/4" barrels, pretty much into .30 carbine territory for that length barrel.

I remember reading somewhere (I think it was dmetrieff) that the bolt weight needed for a straight blowback action to contain .30 carbine proof loads was little more than needed for a 9mm P.

Personal guess is that pistol calibre carbines will give a lot quicker handling, more controllable fire and much less muzzle blast and flash than a .223 carbine.

An additional guess (and a very big one) is that some of the loadings will penetrate more body armour or helmet than you'd want to be wearing in close up and fast action.

Anonymous said...

Yeah, I remember a guy building a pistol round using the 7'62X25 case. He sabot'd the round using a the 62g AP projectiles and came out of a 6" pistol barrel at damn near 2000fps. I 'spect that's a lot more efficient then a full load .223 from a 10" barrel

KurtP said...

Ahhh, yes the M-203- for when granny can't open the door fast enough-- we'll make an entry point she can't ignore!

Firehand said...

On tear gas, I know the standard LE round for a looooong time has been 37mm; they may have gone to a 40mm. Or Colt may be referring to a military-grade gas cartridge.

On a entry gun, doesn't seem to make a lot of sense, since you fire gas into a building and give it a bit to spread around

Anonymous said...

From things I've seen around the net, and you can take that for all it's worth, the 5.56 round actually penetrates less than pistol rounds fired from a carbine. The speed of the round causes it fragment and the smaller pieces lose the ability to go through sheetrock and siding.


Keith said...

I think someone tried to commercialise a sabot loading of the .30 tok as ".223 Timbs"

There are also the .22 Reid (.30 tok necked to .22) and the range of PDW rounds, which seem to be in the same ball park as the .22MMJ/.22carbine (a rimless K hornet) and rimless iterations of .256 Win (necked down .357 mag).

I always chuckle at the supposed poor stopping power of the .30 Luger

It gave the only one shot instant knockdown in the cattle shooting trials which lead to the recommendation that .45" was the minimum calibre suitable for US military service.

Tam said...

1) 5.56 is more likely to incapacitate the target than 9mm, .40, or .45.

2) Paradoxically, 5.56 is less likely to penetrate multiple interior walls than the pistol calibers. This has to do with the velocity of the bullet when it strikes the obstacle and the CoG of a lightly-constructed spitzer rifle bullet versus a thick-jacketed pistol bullet with a much slower yaw cycle... Anyway, safer in buildings for bystanders.

3) For situations where you really need to bring a long gun, bringing a pistol with a shoulder stock doesn't cut it.

They're generally not using anything especially short: The standard Colt LE6920 and the S&W M&P15 tend to be the guns of choice, along with Bushhamster and Rock River products. Suppressors are becoming more common, mostly due to hazardously flammable environments in meth lab raids. Don't want big, booming muzzle flashes when there's phosphine about.

In this respect, they're just following the lead of militaries the world over; the MP5 is so 1990s. About the only place they're used anymore in USSOCOM is performing VBSS work.

Firehand said...

I remember reading something in the 80's about DEA teams raiding labs using suppressed arms just for that reason; I'd wondered if that had become more widespread.