Barrel Length for a Suppressed AR9

[KERTWOOD]

Tros 3-lug 5" is the way to go.

https://trosusa.com/colt-m-16-9-smg-barrels/

 

[Optimus Prime]

Golden Saber, Federal, and Fiochi - all 147gr - goes supersonic out of my Scorpion pistol, 4.5" MPX, and Glock 17. PPU and Freedom HUSH stays subsonic. WWB goes supersonic in the Scorpion but not the MPX or Glock 17.

 

[user 71]

Golden Saber, Federal, and Fiochi - all 147gr - goes supersonic out of my Scorpion pistol, 4.5" MPX, and Glock 17. PPU and Freedom HUSH stays subsonic. WWB goes supersonic in the Scorpion but not the MPX or Glock 17.

i had 147 grain fiochi that wouldn't go supersonic out of my glock 17 or AR SBR 8" ... did you get +P ammo?

 

[Optimus Prime]

i had 147 grain fiochi that wouldn't go supersonic out of my glock 17 or AR SBR 8" ... did you get +P ammo?

Just checked, nope "9APD" standard.

 

[FLdeepdiver]

The 9mm 158gr commercial load was specifically made to address 147gr going supersonic out of a 16” barrel. Ammo varies greatly, but in my experience you will be fine running most 147gr loads subsonic out of barrels 7” or under.

 

[Swine]

Golden Saber, Federal, and Fiochi - all 147gr - goes supersonic out of my Scorpion pistol, 4.5" MPX, and Glock 17. PPU and Freedom HUSH stays subsonic. WWB goes supersonic in the Scorpion but not the MPX or Glock 17.

Thats nuts, def should not be super unless crazy conditions.

Speed of sound at sea level = roughly ~1116.13 feet per second

Most 147's run right at ~1k FPS, should be a decent buffer to NOT be super sonic.

 

[Optimus Prime]

Thats nuts, def should not be super unless crazy conditions.

Speed of sound at sea level = roughly ~1116.13 feet per second

Most 147's run right at ~1k FPS, should be a decent buffer to NOT be super sonic.

Golden Saber and Federal 147 gr are fairly well known for running 1100-1200 ft/sec out of 4.5"-5" barrel, despite manufacturer claims...

I suspect the WWB is transonic and the longer barrel of the Scorpion is responsible for the fairly consistent crack I get... I have no idea on the Fiocchi as it's stated on the box to be 950ft/sec and I have not personally chrono it but given the crack I get I know it is...

 

[Leshaire]

Why are people saying 16" is fine when clearly its no where near ideal for velocity and sound, especially when OP said its a "pistol".....

4.5" is about perfect. That's exactly What my 9mm sbr is.

 

[Piglatinhater]

Why are people saying 16" is fine when clearly its no where near ideal for velocity and sound, especially when OP said its a "pistol".....

4.5" is about perfect. That's exactly What my 9mm sbr is.

Found the detailed guy.

 

[Moondog1]

I have a 4". If you've paid the sbr tax and the suppressor tax, I don't see any advantage to going longer than 4" - unless you're using iron sights and want the longest possible sight radius. FWIW it's louder than my p226 with the same suppressor/ammo. Get the heaviest buffer you can find and put an AR10 spring behind it.

What buffer are you running? I'm looking to increase my buffer weight