i have a 9mm ar pistol with a 5 in barrel that isnt to thrilling.... i just dont like it at all... so i was wondering a few things...


is the longer barrel any quieter suppressed?  (Liberty Mystic is what i have)

is the 16 inch barrel any more accurate at say 100yards...
have i gone crazy? i mean i have sbr's an suppressors an now i am thinking full length....?

It would seem to me that the issue here is any velocity advantage between a 16" bbl and something in a SBR.  I've a tax stamp in process for a 10.5" bbl, with the notion that it will gain velocity compared to a pistol length.  There should be some reason that the lads at Hartford selected that barrel length rather than something shorter, tho' the length of standard carbine handguards may factor into the mix.

I intend to chrono my 16" bbl and then check it again after it's bobbed.  

As regards accuracy, unless there is some fluke of barrel vibration, velocity should tell the tale.  There's no advantage to the longer barrel unless it is assisting the bullet in moving faster at exit.
Moon

SInce you're asking about barrel length and quietness... what type of ammo are you shooting?

The longer brl produces less muzzle pressure. This is easyer for the can to digest making it quieter.

This was my first thought as well. Long barrel, short barrel, if you're shooting supersonics they're gonna sound just about the same suppressed (that is to say, kind of loud). Try some subsonic before changing other stuff.

Unless, of course, you're already shooting subs, in which case, do what you like –– no accounting for personal preference.

what do you not like about your barrel, the accuracy or reliability? suppression is based on several things; a few are,  ammo (velocity and pressure), barrel length, and suppressor itself.

i have a 5" TROS barrel that i love.  it's very accurate for me with factory American Eagle 147gr bullets.  those AE bullets are subsonic and sound great through my TiRant45.  they will likely sound better through my Evo9 but not by too much.  

The only reason i'm going to a 16" barrel is b/c i have a DDLES lower that i will SBR, but i want to put a stock on it now, so will build a full rifle and return it to an SBR once the stamp comes back.

i am using 147 grain subs. i guess i just try to justify every gun i buy an the ar pistol thing just dont get me going. my intention was to sbr it but now i am thinking on just selling the whole setup an going a different route.... an then again i think a 16 in a2 setup may be the ticket to my 9mm ar setup....

Sell your 9mm AR to fund an MP5. The roller lock will give a quieter report due to the delayed blowback.

+ suppressor = winning

Edit: quiter action noise, not quieter report

Echo, weren't you right the first time?  It's my understanding that some of the noise from blowback 9mm carbines is from the ejection port, as there is still pressure and noise when the the breech opens.  It's also my understanding that the H&K breech is longer opening due to the roller lock, so that noise stays in.
Do I misunderstand?
Moon

What kind of buffer are you running?

i use a standard buffer.... it really isnt about the noise. i just dont like the setup. i am gonna try a different host i think.... maybe a 16 inch 9mm. i just dont like the shorty 9mm like i had hoped i would....