BCM SBR Upper - AR15.COM

Posted: 1/26/2018 4:31:05 PM EDT

My BCM lower is getting lonely, time to get this thing built (yes I've got the stamps). Looking for some pics and suggestions.

11.5 Barrel
MLOK Handguard 10, 10.5, 11? Want it as close to the suppressor as I can get.
Will have a Specwar 556 on it

Since I'm building this for the sole purpose of constant suppressor use, what kind of gas block? Any particular BCG?

Posted: 1/26/2018 5:11:51 PM EDT

[#1]

I think the kmr rails were .5 longer than advertised, 10 inch really 10.5 etc.

id go 1 inch shorter than barre to be on the safe side. I have a 10.7 slr rail on a 11.5 and it close with a surefire can but looks great. I don't think the 11 inch rail would clear without extra shims on the muzzle device.

Posted: 1/26/2018 5:32:12 PM EDT

[#2]

I'm just the opposite I picked up a nice BCM .300 Blk I think its a 9.5" barrel with a 9" rail...

Right now its on a Noveske registered lower, but I want to get and F1 a BCM lower so it matches...

Posted: 1/26/2018 6:40:40 PM EDT

[#3]

Wilson makes a sweet 10.5 handguard that looks great on a 11.5.

Posted: 1/26/2018 7:47:38 PM EDT

[#4]

I got what you need

Ballistic Advantage 11.3" that's right 11.3" not 11.5" barrel. Comes with gas block.

BCM upper receiver.

BCM MCMR 10" rail. This rail is actually 10.5" long and with the 11.'3" barrel your suppressor will look nice and flush.

Grab a gas tube and BCM BCG of your choice(Ionbond or regular).

Not worry about OCD

Posted: 1/26/2018 8:05:40 PM EDT

[#5]

Quote History

Quoted:
I got what you need

Ballistic Advantage 11.3" that's right 11.3" not 11.5" barrel. Comes with gas block.

BCM upper receiver.

BCM MCMR 10" rail. This rail is actually 10.5" long and with the 11.'3" barrel your suppressor will look nice and flush.

Grab a gas tube and BCM BCG of your choice(Ionbond or regular).

Not worry about OCD

View Quote

Got some pics?

Posted: 1/28/2018 4:49:08 AM EDT

[#6]

Quote History

Quoted:
I'm just the opposite I picked up a nice BCM .300 Blk I think its a 9.5" barrel with a 9" rail...

Right now its on a Noveske registered lower, but I want to get and F1 a BCM lower so it matches...

View Quote

The shorter BCM .300 barrel is 9" long, and an 8" KMR rail on it will just barely fit cans on many QD mounts.

General sort of rule of thumb is that the longest rail you can run and clear a muzzle device will be 1" shorter than the barrel. They're not really measured the same way.

It also varies by rail manufacturer, so the safe thing to do is search up an image of the rail you want to try with that specific barrel length.

Posted: 1/28/2018 1:40:00 PM EDT

[#7]

My first suggestion is always going to be the Knights rails. They do a 10.75" URX 2/3/4 that always fit perfectly with a 11.5" barrel.

Second choice would be the DD MFR 10 inch rail.

Posted: 1/28/2018 2:02:16 PM EDT

[#8]

I have a bcm 11.5 kmr upper, it’s been a great upper.

My other is a homebuilt larue stealth 12”.

Out of the 2 the 12” is a better shooter and virtually the same weight.

For gb, I use slr adj on all my guns now.

Posted: 1/29/2018 6:36:20 PM EDT

[#9]

BCM 300BLK 9” upper for visual

Posted: 1/29/2018 8:50:18 PM EDT

[#10]

11.5 DD barrel, 10" BCM KMR, F1 suppressor on a Griffin taper mount.

ETA: Before I painted it.

Posted: 1/29/2018 10:45:20 PM EDT

[#11]

Thanks for the pics guys. I was just going to get a complete upper from BCM, but I've decided to just build it; about to start ordering some parts.

BCM Upper
11.5 Faxon Mid length with SA Adjustable gas block
Deciding on handguard, don't see a 10.0" Geissele

Posted: 1/29/2018 10:49:01 PM EDT

[#12]

Look at slr, they make great rails in just about any length.

Bcm 11.5 ——- larue 12” home build (slr rail)

Posted: 1/31/2018 12:30:26 AM EDT

[#13]

Quote History

Quoted:
Thanks for the pics guys. I was just going to get a complete upper from BCM, but I've decided to just build it; about to start ordering some parts.

BCM Upper
11.5 Faxon Mid length with SA Adjustable gas block
Deciding on handguard, don't see a 10.0" Geissele

View Quote

Did you look at that 11.3" barrel yet? It's nice and would tighten up the space you wanted.

Posted: 2/1/2018 1:59:51 AM EDT

[#14]

Here's my BCM 11.5" complete upper w/ an AAC 762SDN6

Posted: 2/3/2018 6:58:57 PM EDT

[#15]

Full 11.5 BCM SBR with an Omega supper: I have a SLR adjustable gas block on mine

Posted: 2/4/2018 1:55:35 PM EDT

[#16]

Quote History

Quoted:
Full 11.5 BCM SBR with an Omega supper: I have a SLR adjustable gas block on mine

https://www.AR15.Com/media/mediaFiles/404018/2017-03-12-10-164125.jpg

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Is that a 10.0" BCM Rail?

Posted: 2/4/2018 8:56:04 PM EDT

[#17]

How about the 13.7” BA Hanson and 13” geissele rail? Fits a can perfectly.

Attached File

Posted: 2/4/2018 10:12:16 PM EDT

[#18]

Quote History

Quoted:
How about the 13.7" BA Hanson and 13" geissele rail? Fits a can perfectly.
https://www.AR15.Com/media/mediaFiles/213456/CBB07355-5BD2-40E3-8740-B26D1F9AB60E-441722.JPG

View Quote

That looks really good. I'm trying to keep the OAL low(er) though.

Posted: 2/5/2018 8:53:17 AM EDT

[#19]

Quote History

Quoted:
That looks really good. I'm trying to keep the OAL low(er) though.

View Quote

No worries. I've got an 11.5" BCM w/ FSP ill probably put a current flavor G rail or 10" ALG rail. I think a 10.5" would be perfect on it. But the .7" difference on the barrel and G rail is about as close as you can get.