Optimal barrel length for 9mm suppressed

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Greenmancgn
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Optimal barrel length for 9mm suppressed

Post by Greenmancgn » Mon Sep 04, 2017 1:45 pm

So maybe my google-fu is weak but I cannot find a answer for best length for projectile stabilization and effective length for powder burn. Projectile will be factory load federal 147 gr FMJ (wadcutters) . I have read everything from 4.5 to 10 inches . Is there a chart or a site that can educate me or if someone can just plain tell me . Thanks in advance . Scorpion evo 3 will be the carbine .

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Re: Optimal barrel length for 9mm suppressed

Post by doubloon » Mon Sep 04, 2017 2:59 pm

By optimal you mean the longest barrel possible where things will remain subsonic?

Not optimal like 22lr where once the barrel is too long the bullet starts coasting?

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Re: Optimal barrel length for 9mm suppressed

Post by Greenmancgn » Mon Sep 04, 2017 3:50 pm

doubloon wrote:By optimal you mean the longest barrel possible where things will remain subsonic?

Not optimal like 22lr where once the barrel is too long the bullet starts coasting?

http://www.ballisticsbytheinch.com/9luger.html
Yes subsonic , Thank you

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Re: Optimal barrel length for 9mm suppressed

Post by JeffWard » Tue Sep 05, 2017 8:59 am

A 3" pistol barrel stabilizes a 147gr 9mm just fine. If you want to keep everything subsonic, I'd go standard pressure 147, and nothing longer than 6-7".

I have 7.5" barrel in mine, and I just bought a 5.5". My 7.5 through a SilencerCo Octane 45K, shooting 147gr round nose "target" loads is easily subsonic. I think 900-950fps?

If you venture up into 115-124gr bullets, and anything +P... you're borderline or definitely supers.

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Re: Optimal barrel length for 9mm suppressed

Post by T-Rex » Tue Sep 05, 2017 9:16 am

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Re: Optimal barrel length for 9mm suppressed

Post by dirtjumper895 » Tue Sep 05, 2017 10:49 am

I can confirm that the difference between 4.5" and 8" is just under 100fps. I run a 148gr flat nose powder coated lead cast projectile( 0.660" long) over 3.3gr of Alliant Bullseye at approx 900fps out of my 226. The same load in my 8" MPX is just under 1000fps. Both barrels stabilize the 148''s no problem out too 100yds with the MPX. This load suppresses well for me in both platforms, with 99% of the powder burnt. 95% of the powder is burnt in the first 2.5" of the barrel.
Last edited by dirtjumper895 on Tue Sep 05, 2017 10:02 pm, edited 2 times in total.
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Re: Optimal barrel length for 9mm suppressed

Post by fishman » Tue Sep 05, 2017 4:53 pm

Bullet stability isn't a function of barrel length, it's purely velocity, twist rate, and bullet characteristics. A 1" barrel will stabilize a bullet, as long as it can get it up to speed.

Asking for the optimal barrel length for suppressed 9mm is like asking for the optimal deer hunting cartridge. You'll get many answers, each having it's own trade offs.
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John A.
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Re: Optimal barrel length for 9mm suppressed

Post by John A. » Tue Sep 05, 2017 5:49 pm

I prefer between 6" and 8.5"

Simply because if I wanted a compact barrel, I would use a compact gun. And I have never had stellar accuracy at longer ranges while using very short barrels either.

If I am shooting a short carbine, I want short carbine length. And I feel the gains in accuracy at longer ranges and the extra space for allowing for better powder burn time are worth a longer barrel. If the powder has completed more burn before it reaches the silencer, should be less first round pop too.
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Re: Optimal barrel length for 9mm suppressed

Post by doubloon » Tue Sep 05, 2017 6:26 pm

fishman wrote:...
Asking for the optimal barrel length for suppressed 9mm is like asking for the optimal deer hunting cartridge. You'll get many answers, each having it's own trade offs.
Pretty much.

I think he's asking for the optimal barrel length for the best suppression for his particular load but it's hard to tell for sure because the question asked is not exactly specific.
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Re: Optimal barrel length for 9mm suppressed

Post by propeine » Wed Sep 06, 2017 10:23 am

Greenmancgn wrote:So maybe my google-fu is weak but I cannot find a answer for best length for projectile stabilization and effective length for powder burn. Projectile will be factory load federal 147 gr FMJ (wadcutters) . I have read everything from 4.5 to 10 inches . Is there a chart or a site that can educate me or if someone can just plain tell me . Thanks in advance . Scorpion evo 3 will be the carbine .
Purchase quickload, figure out what powder is in your wadcutters, put the info in quickload, look for the 100% burn line.

Titegroup will burn in 5" of barrel
AA7 will burn in something like 9" of barrel

I have no idea what powder is in your factory loads though.

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Re: Optimal barrel length for 9mm suppressed

Post by doubloon » Wed Sep 06, 2017 2:26 pm

propeine wrote:...
I have no idea what powder is in your factory loads though.
"clean burning" of course
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Re: Optimal barrel length for 9mm suppressed

Post by Greenmancgn » Wed Sep 06, 2017 8:53 pm

To be more specific , I was looking to see if there was a standard barrel length that would allow for a good marriage between stabilization and ability to keep the projectile subsonic . Reading a bit more online I see that there are a few factors that come into play. I will eventually reload my own but for now I was about to source a good amount of 147 gr flat nose federal 9mm . I had observed this being shot through a kel-tec sub 2000 with a 16 inch barrel and an form 1 build ,I was not impressed with the suppression as there was an audible crack ( supersonic I am guessing) . Thank you for those that answered , I will be seeking out an 8 inch barrel .

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John A.
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Re: Optimal barrel length for 9mm suppressed

Post by John A. » Wed Sep 06, 2017 9:37 pm

The Isreali's used a 10.5" barrel on their uzi's, and they had to go with 158 gr bullets to keep them subsonic. 147's would go super sometimes.

So, that being part of my reason for liking barrels that are around 8.5 inches for 9mm.

This gives more room for achieving full powder burn, while not building up to supersonic velocity.

Also, FWIW, my Lage upper for my M10 submachinegun is also an 8.5" barrel. No problem staying subsonic with 147's.

https://www.youtube.com/watch?v=iLnNKeCCTh0

And my 9mm integral that I built has a barrel that is 6.5 inches long.

Also, no problem staying subsonic and in the lower 1030's or so giving adequate power behind it.
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Re: Optimal barrel length for 9mm suppressed

Post by Greenmancgn » Thu Sep 07, 2017 8:29 am

John A. wrote:The Isreali's used a 10.5" barrel on their uzi's, and they had to go with 158 gr bullets to keep them subsonic. 147's would go super sometimes.

So, that being part of my reason for liking barrels that are around 8.5 inches for 9mm.

This gives more room for achieving full powder burn, while not building up to supersonic velocity.

Also, FWIW, my Lage upper for my M10 submachinegun is also an 8.5" barrel. No problem staying subsonic with 147's.

https://www.youtube.com/watch?v=iLnNKeCCTh0

And my 9mm integral that I built has a barrel that is 6.5 inches long.

Also, no problem staying subsonic and in the lower 1030's or so giving adequate power behind it.
Video is down

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Re: Optimal barrel length for 9mm suppressed

Post by Historian » Thu Sep 07, 2017 8:52 am

In the 1960's European collector of Lugers had one of the rare DWMs
with a suppressor on it. When fired it was acceptably quiet which
was surprising given the 9mm characteristics.

I remembered a YouTube of a P08 with a suppressor that
is interesting:

<< https://www.youtube.com/watch?v=vlXoQMo6Qsg >>

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Re: Optimal barrel length for 9mm suppressed

Post by Historian » Thu Sep 07, 2017 8:55 am

Some added historical Luger information that might be
interesting:

<< http://www.phoenixinvestmentarms.com/1951DWM23SIL.html >>

<< http://i.imgur.com/tYGtL85.jpg >> ... suppressor with matching
serial number.

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Re: Optimal barrel length for 9mm suppressed

Post by John A. » Thu Sep 07, 2017 10:56 am

I have an old sears and roebuck catalog that shows the mausers being imported into the US in the 1908 catalog.

Obviously, none with threaded barrels at that point since that was a bit early.

I found it interesting to see them being imported at that time.
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Re: Optimal barrel length for 9mm suppressed

Post by John A. » Thu Sep 07, 2017 6:54 pm

Greenmancgn wrote: Video is down
Sorry, maybe this will work.

https://www.youtube.com/watch?v=iLnNKeCCTh0
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Re: Optimal barrel length for 9mm suppressed

Post by Greenmancgn » Sun Sep 24, 2017 5:41 pm

John A. wrote:
Greenmancgn wrote: Video is down
Sorry, maybe this will work.

https://www.youtube.com/watch?v=iLnNKeCCTh0
It did thank you

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Re: Optimal barrel length for 9mm suppressed

Post by BlogSarge » Sun Sep 24, 2017 7:06 pm

I have a 5" on my AR SBR. 147s stay subsonic and I was shooting 124 ball and did not hear sonic cracks. I did not use my chrono so I can't tell you exact FPS readings.

As for stabilizing, all shot well and using my Eotech sight and firing relatively quickly I was lobbing rounds into 4-5 inches at 100yards. A better optic and a shooter whose eyes aren't hosed would do much better!

I chose the 5 inch formy max oength since I have a GM-45 can that stays on it all the time and that gives me a handy, easily maneuvered weapon.

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Re: Optimal barrel length for 9mm suppressed

Post by crazyelece » Mon Sep 25, 2017 11:40 am

I might add that you should be careful when using factory 9mm ammo. Some of the factory powder used is very abrasive and if it's not burnt very quickly in a short barrel can cause blast baffle wear.

WWB used to be notorious for this.

Since I reload, I haven't kept current on it.

Also IME, 5-6" is the sweet spot for standard 9mm.

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Re: Optimal barrel length for 9mm suppressed

Post by Greenmancgn » Thu Oct 05, 2017 8:29 pm

crazyelece wrote:I might add that you should be careful when using factory 9mm ammo. Some of the factory powder used is very abrasive and if it's not burnt very quickly in a short barrel can cause blast baffle wear.

WWB used to be notorious for this.

Since I reload, I haven't kept current on it.

Also IME, 5-6" is the sweet spot for standard 9mm.
I will keep an eye on that thank you

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Re: Optimal barrel length for 9mm suppressed

Post by Greenmancgn » Thu Oct 05, 2017 8:29 pm

BlogSarge wrote:I have a 5" on my AR SBR. 147s stay subsonic and I was shooting 124 ball and did not hear sonic cracks. I did not use my chrono so I can't tell you exact FPS readings.

As for stabilizing, all shot well and using my Eotech sight and firing relatively quickly I was lobbing rounds into 4-5 inches at 100yards. A better optic and a shooter whose eyes aren't hosed would do much better!

I chose the 5 inch formy max oength since I have a GM-45 can that stays on it all the time and that gives me a handy, easily maneuvered weapon.
Thank you

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