Velocity in 9mm Carbine

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[ARCHIVED THREAD] - Velocity in 9mm Carbine

Posted: 12/3/2002 12:41:36 PM EDT

Does anyone have any data on 9mm velocity through a longer barrel? I have a 16" Oly, but have not had an opportunity to run it across the Chrono. Just wondering if there is an optimal barrel length.

Thanks, Kirt.

Posted: 12/3/2002 2:57:12 PM EDT

[#1]

about 1325fps from a 16" oly with standard 115gr FMJ.

Posted: 12/3/2002 6:57:50 PM EDT

[#2]

So they are gaining roughly a couple hundred fps, depending on load and such. I thought I read somewhere that the rounds may lose some velocity, due to the longer barrel. Sort of speed up, use all the available powder, then start to drag in the barrel. But if there is any muzzle flash, then there is still powder burning. Ahh, the mystic field of ballistics.

Posted: 12/4/2002 5:58:33 AM EDT

[#3]

I'll add a curve---I chrono'd a handload through both a 10.25" 6 groove 1-10 RH twist and a 16" 4 groove 1x10 RH twist barrel a while back. The load was a 9mm, 124gr RNL-GC (RCBS mold-whel weight), 8gr AA-#7. The 5 shot avg was 1331 and 1334 from both barrels,, remember---AA-#7 is blended for 9mm NATO/Carbine loads, where as most common store 9mm is made for 4-5 pistols.

I think it would be interesting to do a chrono thing using both long and short barrel with various store bought ammo and select handloads.

Posted: 12/4/2002 6:15:43 AM EDT

[#4]

That sounds like what I was thinking about. I have been toying with the idea of going to a 10.5" barrel, with a 5.5 "extension". Most of my 9mm is factory loads, and most of the test data I have seen has been measured from a five inch barrel. Does anyone make a Fake 5.5" FS? Or will this have to fall under pre-ban status? Of course, there isn't much flash from a 16" 9mm using factory loads in the first place.

Posted: 12/4/2002 7:00:26 AM EDT

[#5]

Quoted:
Does anyone make a Fake 5.5" FS?

View Quote

No AR manufacturers I know of makes one(I checked). Just have a machinist make a barrel extension for you and then have a gunsmith permanently attach it.

Or will this have to fall under pre-ban status? Of course, there isn't much flash from a 16" 9mm using factory loads in the first place.

View Quote

I seriously doubt it. Even out of a 10" barrel 9mm isn't going have any powder left to burn. From what I understand the powder is all spent after the first 5"'s, the rest is inertia. Still, if you fire a .223 through a 10" barrel fitted with an extension the flash would be blown out the barrel for all to see. Seems to me that a barrel extension for a 9mm would be OK.

Posted: 12/4/2002 9:24:59 AM EDT

[#6]

Good info all. This has got me thinking that I may go ahead with it. I saw somewhere that maybe DPMS made a slip over FFS, that looked the part, but the barrel was still 14.5", and two inches of extension. I work at a university, which just happens to have a school of engineering, so I may have to slip over there today and see what kind of materials are laying around. Seems i saw a lot of titanium last time I was there...hmmm.

Thanks all, Kirt.

Posted: 12/10/2002 4:17:14 AM EDT

[#7]

Uzis use a 10" barrel which I've been told was optimum for a 9mm.

Posted: 12/10/2002 9:53:08 AM EDT

[#8]

That's what I am thinking also, looking at the info I have been able to find. I have contacted KKF, and after the holidays, I am sending him my barrel to be cut to 10.5", and have a 5.5" FFS installed.

[ARCHIVED THREAD] - Velocity in 9mm Carbine

AR-15 » Rimfire and Pistol Calibers

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