Muzzle Velocity Increase of 9mm Carbines vs Hanguns?

[Logistar]

I am wondering how much increase in muzzle velocity one might expect from a 9mm carbine (such as a Kel-tec Sub2000 or a Hi-Point).

I know that expansion of a JHP round at around 1000 ft/sec is questionable. Would the extra velocity of a longer barrel make expansion significantly more reliable?

Is there any way to calculate the extra velocity of a given 9mm cartridge by a barrel X inches longer than say a four inch barrel?

Would YOU use a 9mm Carbine for self-defensive if you needed to?

I had planned on buying an AR-15 soon. However, I will probably have to put this off about 6 month due to my son's education costs. I am thinking about "plinking" with a cheap 9mm Carbine. (I have LOTS of 9mm ammo and it is cheap here.)

Any thoughts appreciated!!!!

Logistar

 

[Redlg155]

Would the extra velocity of a longer barrel make expansion significantly more reliable?

It depends on the bullet design. Figure to gain anywhere from 100 to 150 fps in velocity for a 9mm from a 16" Carbine. If you used something like Corbon 115gr you are looking about 1400+ FPS.

Is there any way to calculate the extra velocity of a given 9mm cartridge by a barrel X inches longer than say a four inch barrel?

Not that I know of. There is some debate on whether you get any velocity gains past 10" or so of barrel on 9mms due to the fast burning powders. Using the 50fps rule on pistol barrels just doesn't factor correctly for the carbine.

Would YOU use a 9mm Carbine for self-defensive if you needed to?

Yes. It is my backup gun for nasty encounters at home. Remington Golden Saber 124gr+P makes an excellent load. I haven't chronographed them yet, but I figure them to run about 1300+ FPS. Many Law Enforcement Agencies use this cartridge for their MP5 and Colt SMG entry weapons.

I love my little 9mm Carbine. Will it take the place of a full size .223 in all roles? No.

Still, the 9mm is a very economical way to get much needed practice. The low recoil also makes is a great weapon for folks who are recoil sensitive.

Good SHooting
Red

 

[Logistar]

Thanks Red! That's about what I was thinking but I guess I wanted a second opinion.

What I was HOPING everyone would say was something like:

"That 1000FPS in a 4 in barrel would increase to an amazing 5000FPS in a 16in barrel insuring complete fragmentation and complete destruction of any animal on the planet!"

I have a small polymer 9mm for carry. I have a full size Beretta (9mm) for open carry. -(Better range and uses hi-caps). I REALLY like the idea of using the same ammo as much as possible. I was just thinking that the 9mm carbine would give me MUCH more range and a little more power than either of the handguns while using the same cheap ammo I already have.

I would still like an AR-15 but I might just pick up a 9mm carbine first.

Logistar

 

[Onslaught]

Red -

Since you have experience with both 9mm and 5.56 AR's, with the 9mm being straight blowback, is there much difference in felt recoil between the two?

 

[Redlg155]

I consider both the be relatively light recoiling weapons. With hotter or Nato spec loads the 9mm will come closer to the recoil levels of the .223, but the .223 will be slightly more.

A 9mm feels very much like a compensated .223.

Good Shooting
RED

 

[Onslaught]

Thanks Red...

My AR fits my 11yr old very well, but he doesn't like the recoil. He liked my M1 Carbine best, but I don't have it anymore.

He's quite comfortable with 9mm pistols, so I was hoping a carbine in 9mm would be similarly enjoyable.

He's got a Ruger 22/45 and 10/22, but he keeps trying to move up to bigger firearms, in part because he's trying to impress his father, methinks.

 

[Redlg155]

The 9mm AR may very well be a good choice for your son.

My wife shoots the 9mm very well. She isn't quite as comfortable with the .223. Using a load like Winchester 115gr FMJ, the kind you find in 100rd bulk packs will give you very mild recoil. Mount a muzzle brake and you have very little recoil.

The best part about it is that the 9mm can be very accurate in an AR. I've routinely hit the 100 and 200 yard gongs with the 9mm. Plus you can't beat the cheap ammo costs and capability to shoot at indoor ranges where rifles may be restricted.

I think I've used this image before, but if you haven't seen it, it shows just how little the 9mm recoils in an AR15. Two empties are in the air and I can't figure if the third is a live round being fed or an empty being ejected. If you look at the front sling swivel you can also get an idea of how much recoil you have. Judging by the angle, it isnt' very much for rearward movement. It moves even less now that I've had an A3 Tac Brake from Kurts installed.

Good Shooting
RED

 

[444]

I am surprised that your wife finds the .223 uncomfortable. I would say that the recoil of my Colt 9mm is about the same as the .223. Maybe it is the blast of the .223 that adds to the equation ?

 

[Matt G]

Don't underestimate blast in increasing perception in felt recoil. In my own opinion, I'd rather have more recoil and less blast than conversely. Gimme a 10ga NEF handigun over a 16" AR, so long as the 10ga. has a 30" barrel.

Reduced blast and lowered perceived recoil are really the very strongest points in favor of pistol-caliber carbines, IMHO. Because the rounds were loaded for pistol-length barrels, the powders are pretty much completely spent by the time they've pushed that little bullet down 16" of barrel, which makes for a much more pleasurable effect. Even better if you load a really heavy bullet, and it's still subsonic. (I think pretty much all standard factory 9mm loads are going to be supersonic out of 16" barrel, though; even 147g will usually break 1100fps unless it's specifically marked "subsonic".)

 

[444]

That is basically what I was thinking. I love ARs and I love muzzle brakes. I personally don't care that they are louder. I do 99% of my shooting out in the desert with no one else around unless it is a buddy shooting something very similar to me; so the blast isn't much of a factor. The other day I shot a few magazines from my Sten sub-gun then picked up my M4orgery to do some plate shooting. The first shot startled the crap out of me. For some reason I wasn't prepared for the blast/shockwave of that AR. It is definitely there in the .223 caliber.

So what are you guys using for magzines in your 9mm ARs. As I mentioned, I own a Colt AR so I have two 20 round factory Colt mags which were outrageously priced. Then I bought some of those 40 round mags that CDNN sells. And I bought six 30 some round mags of unknown origin from a guy on-line. The two Colt mags run great, but all the rest of the mags are very fussy about what bullet you are using. Hardball is no problem. I have been told that you can tune these mags a little but I think I am just going to be happy with ball ammo. I will never use this rifle for anything other than plinking anyway.

 

[Redlg155]

Maybe it is the blast of the .223 that adds to the equation ?

Definitely. Just the fireball from a .223 in low light conditions can make her flinch.

So what are you guys using for magzines in your 9mm ARs.

I'm using converted UZI magazines. The best one I have is a Rock River converted magazine that I ordered from Donie at SableCo. They seem to run pretty good.

Now if the guys over at Wolff would make replacement UZI springs I would be even happier, but they don't, nor did they express any interest in doing so when I called them.

Good Shooting
RED

 

[444]

I hear you. I wish Wolf would make a lot of springs for the old military stuff and the submachine guns. Hopefully my supply of Sten mags will continue to work throughout my lifetime.
I briefly considered getting a 9mm AR that uses the Sten mags but from what I understand they have to be modified to work in the AR. I don't want to do that because I want to use them in my sub gun. As it turned out, I got a great deal on this Colt, so the point was moot. I haven't owned the rifle long and have not tried all my mags. If they all work I have more than enough to last me.