11.5” BCM SBR? - AR15.COM

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Posted: 1/15/2019 12:53:23 PM EDT

I have searched and came up with several different answers.
I recently purchased a 11.5 SBR. I wanted to run it both suppressed and unsuppressed reliably. I was hoping to just change out the buffer and spring.

Looking for someone who has fired several rounds along with several different kinds of ammo through their rifle.

Do I even need to swap out the buffer or spring?

Thanks

Posted: 1/15/2019 12:57:31 PM EDT

[#1]

I have a BCM 11.5 which I use with an Optimus. No change in function suppressed or not. In fact across a multitude of ARs and cans I have not one which I need to adjust.

Don't spend money fixing problems you don't even know you have yet.

Posted: 1/15/2019 1:24:40 PM EDT

[#2]

I run an H2 in my BCM 11.5 and it runs everything suppressed and unsuppressed perfectly.

Posted: 1/15/2019 1:25:45 PM EDT

[#3]

I have a BCM 11.5. I say shoot it first.

Personally, I went with an A5H3 and LMT Enhanced Bolt Carrier. Did I need to spend the money for that? No, it was working fine suppressed and unsuppressed with a standard H2. But I Like to tinker, so I did.

Posted: 1/15/2019 1:34:47 PM EDT

[#4]

11.5" with enhanced BCG, Geissele spring and H2 buffer. Runs with or without suppressors reliably. I'm going to try an H3 buffer just to see if I can slow it down some more.

Posted: 1/15/2019 3:14:48 PM EDT

[#5]

Do you know what the port size is on the barrel and what type of ammo you will be using? For mixed use i would say a .070 gas port size would be about optimal. You may be able to go a little smaller and still have it reliable with an h2.

I dont personally have one and the posters above say it works fine with mixed use, so you may be good to go. If you want it shooting as soft as possible optimizing the gas port size is a better solution than messing with springs and buffer weights.

I would consider a Black River Tactical gas block insert if you want to get it tuned the way you like it.

Posted: 1/15/2019 3:25:05 PM EDT

[#6]

Quote History

Quoted:
I run an H2 in my BCM 11.5 and it runs everything suppressed and unsuppressed perfectly.

View Quote

Same thing here.

Posted: 1/15/2019 3:36:08 PM EDT

[#7]

Mines a Ballistic Advantage Barrel and Toolcraft BCG with Expo Arms H2 buffs and spring (not BCM) and I run mine both with and without a can reliably without changing a thing.

Posted: 1/15/2019 7:49:10 PM EDT

[#8]

I have a suppressed BCM 11.5" with a Silencerco Specwar 5.56k. With an H2 buffer sometimes it would fail to lock back on an empty mag, no matter how new the mag is. I fixed this by ditching the H2 and getting a bootleg adjustable bcg. No issues before the bcg other than the failure to lock back.

ETA: This failure happened with Wolf Gold .223 and PMC X-TAC 5.56 55 grain.

Posted: 1/15/2019 7:56:16 PM EDT

[#9]

I have a bunch of suppressed SBRs. It will work just fine with and without a suppressor. Personally, I run Bootleg Adjustable BCGs in all my rifles. Doesn’t do anything for reliability, but keeps gas tamed and out of my face.

Posted: 1/15/2019 8:23:25 PM EDT

[#10]

My 11.5 “ BCM with H2 and standard spring and Surefire RC2, ran everything fine no problem. Ejection about 2 o’clock.

Posted: 1/15/2019 9:25:07 PM EDT

[#11]

I have an 11.5" BCM barrel I built an upper with. I use a Superlative Arms adjustable gas block, closed about a 1/3 of the way or so, with an H2 buffer and a fullsize Specwar 556. Works pretty well with M193 or equivalent ammo.

Posted: 1/15/2019 9:35:51 PM EDT

[#12]

Been running my BCM 11.5 for years with a Surefire RC556. H3 buffer from the start with no issues using a wide range of brass cased ammo. I would bet an H2 buffer would be just as well. I use an H2 on my BCM 12.5. Standard carbine springs on both.

Posted: 1/15/2019 10:02:41 PM EDT

[#13]

I am running a 11.5" DD SBR and have had excellent results with XM193, Federal .223, Hornady .223, XM885 and FGMM. Suppressed and Unsuppressed using a H2 buffer.

I am not sure if the rifle came with a H2, as I have moved buffers around a lot and need to document the set ups better.

77

Posted: 1/15/2019 10:05:51 PM EDT

[#14]

I'm running a BCM 11.5" ELW with and without TBAC cans with an H2 and standard carbine spring. Runs great with no stoppages to date in >2k rounds.

Posted: 1/15/2019 10:17:00 PM EDT

[#15]

H3 with standard spring both suppressed and unsuppressed in my 11.5 BHF. Brass case ammo only but it cycled .223 match ammo in addition to a wide range of surplus stuff. H and H2 would probably work just fine. The only issue I ever had with that rifle is when running it on auto, suppressed, with a carbine buffer (bolt was just outrunning the hammer) but it had perfect function when I moved up to the H. My suggestion would be to put in an H3 and call it a day. If you are planning on putting Tula or something through it maybe go with the H2.

Posted: 1/15/2019 11:50:53 PM EDT

[#16]

My 11.5" BCM with a standard buffer spring and H2 buffer. Fires reliably with and without the AAC M4-2000/SDN6 cans regardless of ammo: steel cased, weak pmc 223, 5.56.

Posted: 1/16/2019 10:09:41 PM EDT

[#17]

I run a Daniel Defense 11.5" Barrel with a pinned SLR Nonadjustable gas block, Spikes ST-T2, and Sprinco White spring.

[ARCHIVED THREAD] - 11.5” BCM SBR?

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