WWB 147gr JHP from a 16 inch barrel

[WinstonSmith]

On another thread Alaskapopo said:
Actually a 9mm fired out of a 16 inch carbine is not much if any better than a 9mm fired out of a pistol....

Also when a bullet goes from super sonic to sub sonic it does not de- stabilize. Its accuracy is affected during the transition but it is not de-stabilized. If that was true a lot of snipers using the .308 past 900 yards would not be hitting anything.

Both of these statments are interesting because I shoot WWB 147gr JHP from a Kel-tec Sub2000. I think the 16 inch barrel adds about 150 fps to the muzzle velocity compared to a 4 inch barrel. So I probably have a supersonic bullet at the muzzle and it probably drops below supersonic at about 100 yds (the effective range of the Sub2000).

My questions are:
1. At a range of 100 yds. wouldn't this round from a subbie be more effective (aside from obvious accuracy advantages using a longer sight radius)than the same round from a pistol; and

2. How much inaccuracy should I expect from the supersonic to subsonic transition? Is this a concern for "minute of bad guy" shooting?

[utahglock]

yrs ago while working for Israel Military Industries I had several prototype UZI First Responder Carbines designed for LE use. Chronographed out of the 14 1/2" barrel, 147gr loads had minimual increases.

[WinstonSmith]

Utahglock, do you remember if these were standard factory loads for commercial sale? I thought IMI made +P or hotter loads for the Uzi. I would expect the longer barrel to make more of a difference with slower powder.

The 150 fps that I mentioned was actually for the 115gr WWB. I haven't seen a chrono for 147 gr WWB from a Sub2000? Anybody see data on this?

[utahglock]

I wasn't shooting IMI, but commercial loads from Cor Bon, Rem, Win, Fed-including 115gr, 124gr, and 147gr offerings.

[Merkavaboy]

Somewhere in the back of my mind I recall reading that out of carbines, the 9mm 147gr. loads can actually become slower, thus decreasing their ability to expand.

The whole reasoning behind developing the 147gr. JHP was for increased longer range accuracy out of SMG/carbine length barrels with the possibility of some slight expansion on soft targets (with the emphasis on longer range accuracy rather than expansion).

[xcop]

With the 147 you gain little if any velocity....as was already said you might be losing up to 50fps. That bullet weight uses a fast burning powder for the shorter barrel and frequently will start to lose velocity after 10 inches of barrel.

[WinstonSmith]

Originally posted by xcop
With the 147 you gain little if any velocity....as was already said you might be losing up to 50fps. That bullet weight uses a fast burning powder for the shorter barrel and frequently will start to lose velocity after 10 inches of barrel.
The 147 gr, being heavier than other 9mm rounds, spends more time in the barrel... even a short one. It makes sense that a slower powder would be used with a heavier bullet. So xcop, when you say the 147gr. uses a fast powder, are you saying fast relative to other 9mm ammo or fast relative to rifle ammo?

[James Markov]

Here's some velocities on the 9mm 147 grain out of 2 different carbines.
http://www.hi-pointfirearms.com/documents/guntest.pdf

[cz93x62]

Uh, "sub-sonic" rounds were developed for use in suppressed carbines to remain below 1119 FPs @ sea level. Hypersonic bullets create a "crack" that defeats the purpose of suppression.

Chronography of our duty W-W 147 grain JHP's showed 925-950 FPS from 4"-5" barrels, and 1035-1060 FPS from Colt SMG barrels.

[WinstonSmith]

Originally posted by cz93x62
Uh, "sub-sonic" rounds were developed for use in suppressed carbines to remain below 1119 FPs @ sea level. Hypersonic bullets create a "crack" that defeats the purpose of suppression.

Chronography of our duty W-W 147 grain JHP's showed 925-950 FPS from 4"-5" barrels, and 1035-1060 FPS from Colt SMG barrels.
Interesting because that speed (1119fps) is the speed of sound at 61 degrees Fahrenheit. So if you shot a round at that speed at 60 degrees or colder, you would get a supersonic crack. The measured value of 1060 fps you quote for a Colt SMG would be subsonic down to 8 degrees Fahrenheit, not too bad. And BTW, the "at sea level" notation isn't relevant to speed of sound. Air pressure doesn't matter because it cancels from the equation (http://www.sengpielaudio.com/SpeedOfSoundPressure.pdf).

[WinstonSmith]

Originally posted by James Markov
Here's some velocities on the 9mm 147 grain out of 2 different carbines.
http://www.hi-pointfirearms.com/documents/guntest.pdf
Yep it sure looks like the carbine is not accelerating the bullet much above what would be expected for a handgun. Sure is a big difference between the Highpoint and the Ruger though.

[Washington,D.C.]

Years ago I did some velocity testing of 9mm from different length barrels.I used a lot of 147 grainers too.I was using a TC Contender pistol.What I found was the velocity would increase with barrel length up to a certain point.Then as I got to 16 inches the velocity would start to drop.This was a consistant result.Maybe the gas from the small amount of powder was running out and the friction from the longer barrel was slowing the bullet.There was a length somewhere between pistol and carbine that did give the highest velocity.

[Joe Mamma]

Here's a cut and paste from and old thread of mine:

* * * * * * *
Here are some of my recent tests out of a Glock 17 (4.5" barrel) and a Kel-Tec Sub 2000 carbine (16.1" barrel). I used the Kel-Tec because I was curious to see how much velocity would be gained by a longer barrel with the various ammo that I tested. Everyone has a theory but, one test is worth a thousand theories.

If it matters, testing conditions were about 40 degrees farenheit. All testing was done on the same day.

I am by no means an authority on ballistics. I welcome all feedback and comments.


Ammo Description (Product Code)
average velocity with G-17, average velocity with Kel-Tec Sub 2000

1. Federal NATO, 124gr FMJ (M882)
1114, 1231

2. Federal Hydra-Shok 124gr +P+ JHP (P9HS3G1)
1167, 1321 :)

3. Winchester USA Brand ("White Box") Hollow Points 115gr JHP (USA9JHP)
1149, 1305

4. Winchester USA Brand ("White Box") Hollow Points 147gr JHP (USA9JHP2)
1020, 1117

5. CCI Blazer Brass 115 gr FMJ (5200)
1120, 1299

6. CCI Blazer Aluminum 115gr FMJ (3509)
1153, [did not test in my Kel-Tec b/c aluminum cased ammo is not recommended; but, I was tempted . . . ]

7. Sellier & Bellot 115 gr FMJ (80166-00902)
1162, 1296

8. Geco/Dynamit Nobel 124gr (23364-12585)
1129, 1256

9. Magtech 147gr "FMC-FLAT" (891798-001347)
969, 1096
* * * * * * *

Joe Mamma

[GroovedG19]

Good info, Joe Mamma.Thanks

[WinstonSmith]

A friend of mine in Kentucky just did some chrono measurements on the Keltec Sub2000 and a Kahr PM9 with a 3" barrel. All measurements at 15 ft from muzzle and at 64 degrees F. Here are the results:
Win 147 gr JHP - Five shots through the SUB-2000:
1111 FPS
1139 FPS
1119 FPS
1136 FPS
1130 FPS

1139 FPS - High
1127 FPS - Average
1111 FPS - Low
28 Extreme Spread
11 Standard Deviation

Win 147 gr JHP - Five shots through the Kahr PM9:
938 FPS
923 FPS
910 FPS
934 FPS
915 FPS

938 FPS - High
924 FPS - Average
910 FPS - Low
28 Extreme Spread
11 Standard Deviation

Maybe there is some intermediate barrel length that would do even better but the 16" barrel is clearly faster than the Kahr PM9 or Glock 17.

[WinstonSmith]

.

[EdTracker]

I wonder what the velocity increase would be with a hand loaded slow burning powder such as blue dot. If you get a lot of muzzle flash with a given load from a shorter barrel I would think that you would see more of a gain going with a carbine length barrel.

[SurveyMan]

Well what I need is a good recipe for 147gr. Rainier flat nose 9mms that will be shot out of a Colt RO635 10" upper (on an SBR and not a ghey pistol) and they'll also be used on a 92fs- both suppressed.

I'm more worried about getting the load right for the Colt than the 92fs. If I get the right load for the Colt and out of the Beretta it's louder or slower or whatever, I can live with it. I do NOT want to get a great quiet round for the 92fs and have it not cycle the Colt.

I just got a new Lee classic 4 hole press and we did some testing in the garage last night with H110. Not fast enough! Also I didn't have a good chart for H110 and we had to start low and go up. We started so low that rounds were literally falling out of the suppressor. Well actually they weren't falling out, they were scraping the front baffle and tumbling out.

[357glocker]

Here are my results using a G26 and a Marlin Camp9

Silver Bear 145grHP G26: 979fps MC9: 1073fps

Remington 115grFMJ G26: 1074fps MC9: 1261fps

Corbon 115HP +P G26: 1306fps MC9: 1539fps

WWB 115grFMJ G26: 1108fps MC9: 1333fps

Blazer Brass 115FMJ G26: 1084fps MC9: 1374fps

These are all 10 shot avg's except the corbon which was 5 shots from each firearm.