AR platform 9mm

[krw]

In an AR plaform 9mm, what would be the difference in velocity between 5” an 8” barrel? I wouldn’t think very little??

Is there any appreciable difference between RDB BCG/Bbl combo and just std mil-Spec?
Thanks!!

 

[Redlion]

For what it is worth, an 8" barrel is considered by some to be the best balance between shortish barrel length and performance. A reason why the CZ Scorpion Evo 3+ has a 7.9" barrel.

 

[charbroiled]

What ammo? Subsonic 147gr or some flavor of +P+?

 

[MadDuner]

In an AR plaform 9mm, what would be the difference in velocity between 5” an 8” barrel? I wouldn’t think very little??

Is there any appreciable difference between RDB BCG/Bbl combo and just std mil-Spec?
Thanks!!

I don't know where the "sweet spot" is for 9mm, but I do have some chrono data from some Federal 124gr +P HST.
Sig P290RS 2.2" barrel = 977fps
CZ SP-01 4.6" barrel = 1200 fps
CZ Scorpion 16" barrel = 1361 fps

So I would guess that an 8" barrel is going to be between the last two at 1250 fps or so?

 

[krw]

All the 147gr I have now stays subsonic in 5” AR Platform. I always shoot it suppressed also

 

[bfoosh006]

http://www.ballisticsbytheinch.com/9luger.html
As per this link ... it would depend on the specific load.
IE , Generally, +P loads would benefit more that "bulk'ish" , lower speed , priced ammo.
In context to sub-sonic loads .. not much increase velocity wise.

FWIW... here is a bunch of 16" velocities... maybe it can help a little. And FWIW... one of these days I will get around to a 10.5" full test, Lol
https://www.ar15.com/forums/ar-15/-/16-712312/?page=1&anc=7429025#i7429025