Why so few 40 sub machine guns?

[Ghengisconrad]

So I am in love with the 40 caliber bullet, especially of course in a pistol, it can achieve great speeds, but all you ever see in submachine guns or rifles that shoot handgun cartridges is 9-mm and occasionally a 45, but never 40 cal!

Por qué?

Really, I would like to have a huge stockpile of ammo and parts and have as few parts and ammo types as possible, so if I was going to buy/make a 40 cal AK Rifle, would that be silly? Is there some reason, or is it just the effect of standardization? I've seen AKs in 9mm, and even in 45, but have never heard of a 40 cal.

 

[Conqueror]

9mm and .45 were already well-established when .40 showed up. My bet is that many manufacturers were just too lazy to re-tool their production lines when the other two were already so popular.

 

[[Pb]]

Pistol caliber subguns are losing favor to short barreled .223 and even 5.7 carbines. It's just not the focus of new R&D for most gun manufacturers, and like the above said, 9MM and .45 carbines are already very well established.


If you want one, Beretta makes a Cx4 carbine in that caliber.

 

[briansmithwins]

Most of the classic subgun designs came out in WWII or shortly thereafter. By the time 40 S&W was developed the sun had pretty much set on the subgun. Short versions of assault rifles have pretty much displaced them except for PDWs, which are another post. BSW

 

[wishin]

That's a very good question. My guess, because I don't now the answer, is that gun companies don't feel there's a good enough market out there to justify and then sustain production of one. Therefore, poor return on investment (ROI) .

 

[Coronach]

.40 was catching on as a sidearm caliber about the same time that the SMG was going out of favor. In a constricting market, it probably didn't make sense to offer a .40 caliber SMG when 9mm and .45 (especially 9mm) was so well-established.

Mike

 

[Runningman]

but all you ever see in submachine guns or rifles that shoot handgun cartridges is 9-mm and occasionally a 45, but never 40 cal!

Ruger sold the PC4 carbine in 40 S&W for about 10 years. Seems like not many people besides myself bought one.

 

[LibShooter]

I don't think any military organization uses .40, do they? Since those are the major customers for SMGs and they're already well supplied with guns using 9mm and .45, it would be a hard market for a .40 machine gun to crack.

 

[Mandolin]

Thre's the UMP40 and the MP5/40, both from HK. I don't know of any others

 

[General Geoff]

I just bought a Kel-Tec Sub2000 folding carbine in .40S&W last weekend. It's sweet.

 

[freakshow10mm]

Limited market for machine guns and submachine guns in the US means you must be NATO compliant which means 9mm which also sucks out of a subgun. The .45 offers a lot better terminal performance from a subgun but the increase noise and recoil default them to the 9mm. Now we have subguns like the Kriss in .45 with the recoil of a 9mm on full auto.

 

[Wes Janson]

.40 S&W was introduced in 1990.

The NFA Registry was closed to registration of new transferable machine guns in 1986.

You can see the problem.

 

[CornCod]

Pb is right. Pistol caliber sub-machine guns are losing ground to the new cartridges designed for firearms built on the PDW concept like 5.7, Heckler &Koch's 4.6X30mm and the Red Chinese 5.8X21mm. These rounds are probably poor manstoppers, but they have the chief advantage of having good performance against body armor. This is not a consideration for civilian self-defense, but just the military. On the other hand, 10mm makes a lot of sense in a semi-auto carbine for civilian homeowners in rural areas.

 

[Ghengisconrad]

Yeah, the idea is to just take an off the shelf bulpup AK, convert it to a 40 cal receiver and put a butt pad right at the end of the action. 8 inch action plus 16 inch barrel and a 2 inch butt pad is 26 inches of pure compliance, in a length of an UMP40 with more bullet, more speed, and the reliability of a Kalishinokov (with my WASR10 and Saiga 308 will make my collection complete)...

Also, if the zombies ever attack, or laws are ever made more sane, AK actions are easy to convert.

I like to imagine there are parts of my gun collection that can be buried in dirt and still work like magic.

 

[NG VI]

Pretty sure that easily converted actions to any firearm haven't been sold in the US in quite some time, the ATF started cracking down on open-bolts and easy conversions what, twenty years ago? longer?

 

[Sam1911]

just take an off the shelf bulpup AK, convert it to a 40 cal receiver and put a butt pad right at the end of the action.

Do you have a plan for how to design this conversion? I'm curious how you figure on feeding (what mag? what mag well?), what lockup (blowback, I'd guess...how will you convert the bolt & carrier?), what barrel, what do do with all the extra cycling length, etc.

If you're serious about this conversion, you're either an accomplished machinist and designer ... or you're about to become one.

There were a bunch of really interesting conversions done by the guys over at AKfiles.com back when parts kits were a dime a dozen. Some were pistol caliber/blowback arrangements. Lot of work involved. Love to see you accomplish your goal -- and how you do so!

-Sam

 

[Ghengisconrad]

My understanding is that if I can make a new receiver, I will be good. I got some schematics and will adjust them to fit. I'm thinking i'll eihter make my own mag, or just use UMP40 mags. Other than that, get a custom barrel made and it should be fine. I'm looking into people who have converted AKs to 9mm, and the blowbAK pistol schematics as a study guide.

I really have no idea what I'm doing, but I know that its possible. From there it will just be time. If it takes years thats fine, but when I'm done, I'll have my dream. A tactically sized .40 sub-machine style rifle.

 

[Speedo66]

My understanding is that if I can make a new receiver, I will be good. I got some schematics and will adjust them to fit. I'm thinking i'll eihter make my own mag, or just use UMP40 mags. Other than that, get a custom barrel made and it should be fine. I'm looking into people who have converted AKs to 9mm, and the blowbAK pistol schematics as a study guide.

I really have no idea what I'm doing, but I know that its possible. From there it will just be time. If it takes years thats fine, but when I'm done, I'll have my dream. A tactically sized .40 sub-machine style rifle.

Save your self much hardship and buy a Kel-Tec Sub2K in .40.

It's cheap, and it works, probably 2 things your self made gun won't be or do, based on your comment "I really have no idea what I'm doing".

2 points for honesty though.

 

[Quiet]

The H&K MP-5/40 was discontinued at the turn of the century.
It's also one of the reasons why there were some many HK94 clones in .40S&W on the market.
FFL/SOT dealers were demilling police trade-in H&K MP-5/40s into parts kits to use for semi-auto builds.

 

[msiley]

Berretta PX4 Storm is in .40.

 

[msiley]

Also, Microtech is creating a pistol caliber carbine out of their STG/E4 platform. Not
sure if it will be in .40.

 

[Col. Plink]

Or go get a HiPoint 40carbine off budsgunshop.com for under $200

I was able to trade some ammo for a lightly-used one, change the rear sight for the mount included, put on some closeout quad-clamp rings and 4x BSA scope from WalMart for a pleasingly accurate plinker for next to nothing. The carbine-length barrel really makes the .40 pop!