9mm AR with a can - Edumacate me on barrel length

[AirOpsMgr]

I'm contemplating a 9mm AR build, probably something basic like a PSA build, but I'm curious about performance with a can (Octane 45).

I don't want a pistol, nor do I really want to spend the additional $ on a form 1 stamp to go the SBR route..... so, what it really boils down to is, is it even worth suppressing a 16" 9mm?

On average, will 9mm subsonic (say 147gr) remain subsonic out of a 16" barrel?

 

[rOmiLaYu]

http://www.ballisticsbytheinch.com/9luger.html

 

[AirOpsMgr]

http://www.ballisticsbytheinch.com/9luger.html

Look, I'm not John Nash, way too many numbers and columns. Maybe if there were more pictures

 

[rOmiLaYu]

Look, I'm not John Nash, way too many numbers and columns. Maybe if there were more pictures

Basically, depending on ammo manufacturer, 147gr 9mm should mostly still be sub sonic out of a 16" barrel. 158gr for sure. 147gr mostly probably.

 

[AirOpsMgr]

Basically, depending on ammo manufacturer, 147gr 9mm should mostly still be sub sonic out of a 16" barrel. 158gr for sure. 147gr mostly probably.

I was a little confused as I did not see anything specifically listing "subsonic" ..... yes, bare with me, I'm a noob.

So, from a decibel standpoint, I could go ahead and play around with a 16" 9MM AR and not notice too much of a difference in barrel length?

 

[Willy Leadwell]

One extra night of manwhoring will more than pay for the cost of the stamp.

 

[PewPewPewCo]

147 will stay subsonic at all barrel lengths unless the manufacturer is a full blown retard(cough cough Summit Ammo)

 

[rOmiLaYu]

I was a little confused as I did not see anything specifically listing "subsonic" ..... yes, bare with me, I'm a noob.

So, from a decibel standpoint, I could go ahead and play around with a 16" 9MM AR and not notice too much of a difference in barrel length?

Correct, Dick Monster.

 

[PewPewPewCo]

but honestly, 16" 9mm ar seems silly to me. wish the sig brace was still in vogue for those one off builds.

 

[AirOpsMgr]

Correct, Dick Monster.

That was a little harsh, wasn't it?

By the way, your mom's phone seems to be turned off at the moment, would you mind conveying to her that I'm also good for the same time at the Masters Inn off of I75/Exit 218 tomorrow night?

 

[AirOpsMgr]

but honestly, 16" 9mm ar seems silly to me. wish the sig brace was still in vogue for those one off builds.

Clue me in here, why is 16" silly? too long? not enough suppression? Take me to school.

 

[AirOpsMgr]

One extra night of manwhoring will more than pay for the cost of the stamp.

You obviously don't know how cheap I am

 

[PewPewPewCo]

Clue me in here, why is 16" silly? too long? not enough suppression? Take me to school.

1. 9mm doesn't really benefit from barrel lengths beyond 5" or so. (357 on the other hand is incredible in long barrels, buy my Rossi 92)
2. its a direct blowback design, so you want the pressure to leave the barrel ASAP, rather than hang around and come out back end when the bolt moves back leading to port pop. (lever actions don't have port pop, buy my Rossi)
3. 16" is wieners, 16" + suppressor is super wieners. (um, buy my Rossi?)
4. the 16" can be quieter IMO than the 9mm, but you may find yourself having to play with buffers to eliminate port noise.

Maybe see if Dobbs would weld up a tube to the barrel for an SBX style barrel?

 

[rOmiLaYu]

By the way, your mom's phone seems to be turned off at the moment, would you mind conveying to her that I'm also good for the same time at the Masters Inn off of I75/Exit 218 tomorrow night?

Done.

She said his name would be "Marco" and that the safeword was "Avocado."

 

[AirOpsMgr]

1. 9mm doesn't really benefit from barrel lengths beyond 5" or so. (357 on the other hand is incredible in long barrels, buy my Rossi 92)
2. its a direct blowback design, so you want the pressure to leave the barrel ASAP, rather than hang around and come out back end when the bolt moves back leading to port pop. (lever actions don't have port pop, buy my Rossi)
3. 16" is wieners, 16" + suppressor is super wieners. (um, buy my Rossi?)
4. the 16" can be quieter IMO than the 9mm, but you may find yourself having to play with buffers to eliminate port noise.

Maybe see if Dobbs would weld up a tube to the barrel for an SBX style barrel?

Okay, makes sense - I had not even considered the blow-back design, Thanks!

Guess you aren't just a pretty face after all

 

[PewPewPewCo]

Done.

She said his name would be "Marco" and that the safeword was "Avocado."

i forget how the rest goes, but you mother's a pimp

 

[Willy Leadwell]

I did some ballistics testing on this last night and found that the longer the barrel, the deeper the penetration.

 

[PewPewPewCo]

I did some ballistics testing on this last night and found that the longer the barrel, the deeper the penetration.

that's certainly interesting, velocity on 147 grain only gets very marginally greater beyond the first few inches. Like less than 100fps different.

 

[Hoss]

that's certainly interesting, velocity on 147 grain only gets very marginally greater beyond the first few inches. Like less than 100fps different.

On a blowback action, where is the velocity apex on 147gr 9mm? My guess would be somewhere around 10"

 

[Willy Leadwell]

Yeah, that was supposed to be a sex joke, but clearly a fail.