Best (most reliable) barrel length for a 9mm SBR?

BerdanSS · December 24, 2014, 09:52 PM

I've been lusting after a 9mm AR SBR for years now. Something along the lines of a 9mm take on the MK18. I have a couple extra parts laying around I've been mentally holding for it, LMT SOPMOD, gasbuster CH and so on, but never really got down to it. Well my wife tells me today that part of my Christmas gift from her this year, is a small frame glock mag lower from Quarter Circle 10 that I've been drooling over for the last couple weeks.

Now doing a loosely based MK18, I was going to go with a 10.5" barrel. This carbine will not be suppressed all the time. But when it is it will most likely have a YHM wraith spun on it. Is 10.5" a good length for reliability both suppressed and un-suppressed? Are there any lengths that cause reliability issues for sure without heavy tweaking?

Ridge_Runner_5 · December 24, 2014, 11:22 PM

9mm is blowback, not gas operated, so any barrel length should function the same way.

Sure shot wv · December 25, 2014, 02:16 PM

I'm in the process of building one now. It will 99 percent of the time have a huntertown arms guardian 9 on it. Im going with a 5inch barrel. My thought process was (even tho i do hand load ) 1) it will be easier to stay subsonic with the shorter barrel and 2) since it will have the can on the majority of the time I wanted a shorter overall package.

I've been looking at adco barrels the most in that length. Who all have you looked at?

Sharkbite · December 25, 2014, 03:06 PM

I have a 10" barrel on a QC10 lower. Im going to start shopping around for a shorter tube. Like 5" or so. Since its an SBR it might as well be as short as possible.

As stated above the 9mm is a blowback system so barrel length will not effect operation, and the gas buster CH is wasted on a non-gas gun IMO.

BerdanSS · December 25, 2014, 09:36 PM

Sharkbite

Ya I know the real purposes of the gas buster is a wash on one, I just have an extra laying around. But I'm almost debating using something more more like a mod 4 gunfighter....just because of putting W&T on the PRI with the price tag they have. I could keep it in reserve for my MK12.

I didn't think about the length being a non issue due to blowback

I've looked at ADCO, RRA and YHM. But I'm leaning toward an ADCO 7" now.

Mobuck · December 26, 2014, 07:45 AM

9mm is blowback, not gas operated, so any barrel length should function the same way.

Not even sure the "gas buster" CH is necessary.

December 24, 2014, 09:52 PM	#1
BerdanSS Senior Member Join Date: April 3, 2011 Location: to close to other houses Posts: 1,176	Best (most reliable) barrel length for a 9mm SBR? I've been lusting after a 9mm AR SBR for years now. Something along the lines of a 9mm take on the MK18. I have a couple extra parts laying around I've been mentally holding for it, LMT SOPMOD, gasbuster CH and so on, but never really got down to it. Well my wife tells me today that part of my Christmas gift from her this year, is a small frame glock mag lower from Quarter Circle 10 that I've been drooling over for the last couple weeks. Now doing a loosely based MK18, I was going to go with a 10.5" barrel. This carbine will not be suppressed all the time. But when it is it will most likely have a YHM wraith spun on it. Is 10.5" a good length for reliability both suppressed and un-suppressed? Are there any lengths that cause reliability issues for sure without heavy tweaking? __________________ One day, Men in tall hats will thump their chests and proclaim..."oh, what a great sea of mud we lived in"--The unalterable fate of billy creek .... "Smoke.....it's what's for dinner"

December 25, 2014, 09:36 PM	#5
BerdanSS Senior Member Join Date: April 3, 2011 Location: to close to other houses Posts: 1,176	Sharkbite Ya I know the real purposes of the gas buster is a wash on one, I just have an extra laying around. But I'm almost debating using something more more like a mod 4 gunfighter....just because of putting W&T on the PRI with the price tag they have. I could keep it in reserve for my MK12. I didn't think about the length being a non issue due to blowback I've looked at ADCO, RRA and YHM. But I'm leaning toward an ADCO 7" now. __________________ One day, Men in tall hats will thump their chests and proclaim..."oh, what a great sea of mud we lived in"--The unalterable fate of billy creek .... "Smoke.....it's what's for dinner"

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December 24, 2014, 11:22 PM	#2
Ridge_Runner_5 Senior Member Join Date: February 8, 2008 Location: Denver, CO Posts: 1,925	9mm is blowback, not gas operated, so any barrel length should function the same way.

December 25, 2014, 02:16 PM	#3
Sure shot wv Senior Member Join Date: January 25, 2013 Location: West Virginia Posts: 137	I'm in the process of building one now. It will 99 percent of the time have a huntertown arms guardian 9 on it. Im going with a 5inch barrel. My thought process was (even tho i do hand load ) 1) it will be easier to stay subsonic with the shorter barrel and 2) since it will have the can on the majority of the time I wanted a shorter overall package. I've been looking at adco barrels the most in that length. Who all have you looked at?

December 25, 2014, 03:06 PM	#4
Sharkbite Senior Member Join Date: November 4, 2013 Location: Western slope of Colorado Posts: 3,679	I have a 10" barrel on a QC10 lower. Im going to start shopping around for a shorter tube. Like 5" or so. Since its an SBR it might as well be as short as possible. As stated above the 9mm is a blowback system so barrel length will not effect operation, and the gas buster CH is wasted on a non-gas gun IMO.

December 26, 2014, 07:45 AM	#6
Mobuck Junior member Join Date: February 2, 2010 Posts: 6,846	9mm is blowback, not gas operated, so any barrel length should function the same way. Not even sure the "gas buster" CH is necessary.