Sbr? [Archive] - Glock Talk

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B.Reid
12-20-2011, 17:41
I just ordered a striped lower and am thinking about a short barreled rifle. What barrel length do you guys recommend? It will be a 5.56 and I want it in the 10 to 11 inch range. Any suggestions or warnings of what to stay away from. I am in no hurry and expect this to take months. Also where do I get the ATF paperwork?

NeverMore1701
12-20-2011, 19:19
I'd do 11.5".

B.Reid
12-20-2011, 19:41
I'd do 11.5".

Probably a likely choice. But why that length?

BBJones
12-20-2011, 19:55
12.5 if it was me. Balance of reliability and ballistics without being too long.

zhix
12-20-2011, 19:58
I would go as short as 8.5" if I were to get one in 9mm but in 5.56 I wouldn't go shorter than 10.5" just because for me anything shorter would be pointless. I have heard that with most suppressors it is reccomended to have an 11.5" or longer barrel.
I bought a factory built stag arms 11.5 model that had to go back three times to make everything right. It works now but if it weren't an SBR I would have sold it a long time ago because I don't want to own anything made by a company that sucked so badly at customer service, even after speaking with the owner (and being lied to) in person.

chemcmndr
12-20-2011, 20:46
For 5.56mm I wouldn't go shorter than 10.5". My first SBR AR was an 11.5" and I love it. If you want to go 9mm, I personally prefer the 7" barrel over the 10.5" ones. It seems that with the 5.56mm, going below 10.5" you start to run into reliability issues unless you do some major tweaking to the rifle. Also, the barrel length really cuts down on the effective range of the 5.56 cartridge from a terminal ballistics standpoint.

As for the ATF paperwork:

http://atf.gov/forms/firearms/

you will need two copies of 5320.1 (Form 1) and one copy of 5330.20 (Certification of Compliance).

boomhower
12-22-2011, 04:01
I wouldn't go shorter than 11.5. If I ever do SBR it will like be a kino upper from BCM. If you want really short take a look into 300 BLK. It really shines out of very short barrels compared to 5.56.


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PlasticGuy
12-22-2011, 06:13
It's very difficult to make a 5.56 AR15 reliable with a barrel shorter than 11.5". Shorter than that, and you get very high gas port pressure and very short dwell times, which makes for very fast cycling of the action. This is harder on the bolt and other moving parts, and demands a lot more from the magazines to keep rounds feeding quickly enough.

A 9mm can be very short and still work. So can a .300 Blackout and a few others. If you want an AR15 shorter than 11.5", you should consider moving away from the 5.56 cartridge.

JASV.17
12-22-2011, 06:24
Good read...

http://www.ar15.com/forums/t_2_138/174764__Q__Why_BCM_chose_the_11_5_SBR_over_the_10_5_.html

CAR-AR-M16
12-22-2011, 07:19
12.5 if it was me. Balance of reliability and ballistics without being too long.

12.5" for me as well.

http://img.photobucket.com/albums/v389/CAR-AR-M16/Machinegun-M16-1.jpg

shadow65
12-22-2011, 11:40
10.5" in a 5.56. If you go 11.5" you will still want a 10.5". Ask me how I know:whistling:

M&P15T
12-22-2011, 14:01
12.5" for me as well.

http://img.photobucket.com/albums/v389/CAR-AR-M16/Machinegun-M16-1.jpg

At 12.5", I think doing the paper-work and paying the fees wouldn't be worth it. I'd just get a 14.5" mid-length and enjoy it.

CAR-AR-M16
12-22-2011, 14:54
At 12.5", I think doing the paper-work and paying the fees wouldn't be worth it. I'd just get a 14.5" mid-length and enjoy it.

What you said makes sense, but I paid my $200 tax because my gun is a registered receiver full-auto, so I could have used any length barrel I wanted. For me, the 12.5" is the best compromise when it comes to ballistics vs. compactness. YMMV

B.Reid
12-22-2011, 14:58
At 12.5", I think doing the paper-work and paying the fees wouldn't be worth it. I'd just get a 14.5" mid-length and enjoy it.

That is the other thing I am thinking about. But those short ones are just so cute.

Scattergun1187
12-22-2011, 15:04
Here is my CMMG 10.3" SBR. Has been flawless and reliable. (CMMG haters out there) I also have a BCM 14.5 on a BCM Lower.
http://i655.photobucket.com/albums/uu278/4layercake/002.jpg

jrs93accord
12-22-2011, 15:07
LMT 10.5" is the standard by which all others are measured.

http://i100.photobucket.com/albums/m8/jamesrea_2006/jamesrea_08/jamesrea09/002-3.jpg

http://i100.photobucket.com/albums/m8/jamesrea_2006/jamesrea_08/jamesrea09/001-3.jpg

http://i100.photobucket.com/albums/m8/jamesrea_2006/jamesrea_08/jamesrea09/003-3.jpg

WoodenPlank
12-22-2011, 15:38
I just ordered a striped lower and am thinking about a short barreled rifle. What barrel length do you guys recommend? It will be a 5.56 and I want it in the 10 to 11 inch range. Any suggestions or warnings of what to stay away from. I am in no hurry and expect this to take months. Also where do I get the ATF paperwork?

The ATF paperwork can be ordered directly from the ATF website, or printed out. You will need two copies of the Form 1, and a single Certification of Compliance. These two forms can be printed, and you can even enter your info directly into the form before printing it. You will also need TWO fingerprint cards - these can NOT be printed, and must be ordered directly from the ATF. They will gladly mail them to you for free, and only take a few days to get in. If you are going to use a trust for the paperwork, however, you do NOT need the fingerprint cards, but instead submit a copy of your legal trust paperwork.

Current wait time on paperwork is between 4 and 6 months once submitted.

LMT 10.5" is the standard by which all others are measured.

http://i100.photobucket.com/albums/m8/jamesrea_2006/jamesrea_08/jamesrea09/002-3.jpg

http://i100.photobucket.com/albums/m8/jamesrea_2006/jamesrea_08/jamesrea09/001-3.jpg

http://i100.photobucket.com/albums/m8/jamesrea_2006/jamesrea_08/jamesrea09/003-3.jpg

I run the same upper, just significantly modified, and it has been nearly flawless. The only problem I have had is it didn't like the crappy Tula ammo from Walmart before I switched to a Noveske KX3 FH. If I had to do it all over again, I probably would have gone for a BCM 11.5" with standard FH or similar, but I still love my LMT upper.

Scattergun1187
12-22-2011, 16:04
Been looking at a BCM 11.5 BHF barrel Upper. I'm concerned on the fit to the CMMG lower.
Keep in mind all internal parts are custom for all those CMMG haters.
I had a LMT 10.5 Upper, but sold it.

WoodenPlank
12-22-2011, 16:09
Been looking at a BCM 11.5 BHF barrel Upper. I'm concerned on the fit to the CMMG lower.
Keep in mind all internal parts are custom for all those CMMG haters.
I had a LMT 10.5 Upper, but sold it.

Upper/lower fit is often a crapshoot, but I wouldn't sweat it much.

Scattergun1187
12-22-2011, 20:56
The ATF paperwork can be ordered directly from the ATF website, or printed out. You will need two copies of the Form 1, and a single Certification of Compliance. These two forms can be printed, and you can even enter your info directly into the form before printing it. You will also need TWO fingerprint cards - these can NOT be printed, and must be ordered directly from the ATF. They will gladly mail them to you for free, and only take a few days to get in. If you are going to use a trust for the paperwork, however, you do NOT need the fingerprint cards, but instead submit a copy of your legal trust paperwork.

Current wait time on paperwork is between 4 and 6 months once submitted.



I run the same upper, just significantly modified, and it has been nearly flawless. The only problem I have had is it didn't like the crappy Tula ammo from Walmart before I switched to a Noveske KX3 FH. If I had to do it all over again, I probably would have gone for a BCM 11.5" with standard FH or similar, but I still love my LMT upper.

I noticed you have your anti-roll pins in backwards. The pin that you tighten goes in the lower hole. But that's just what the instructions say.

Big Bird
12-22-2011, 21:08
I have a LMT 10.5" gun and it runs great with all kinds of ammo. I had some problems with it short stroking at first but after I called LMT and they asked me what weight buffer I was running in the gun they told me to switch to the standard weight carbine buffer (I was running an H2 buffer). They said their gas ports are set up for the lighter buffer and the heavier buffer would cause the malfunctions I was experiencing. Once I went to the lighter buffer everything was right with the world and 1500 rounds later there hasn't been a single problem. Couldn't be happier and there's no evidence of excessive wear on any parts.

WoodenPlank
12-22-2011, 21:10
I noticed you have your anti-roll pins in backwards. The pin that you tighten goes in the lower hole. But that's just what the instructions say.

That's not my lower. :whistling:

jrs93accord
12-23-2011, 07:35
I noticed you have your anti-roll pins in backwards. The pin that you tighten goes in the lower hole. But that's just what the instructions say.

Those are some early KNS pins. Both pins have screws to secure the support. Newer generation pins have only one side that has screws. You are correct about the lower pins having the screws in them. The upper pins have the key that protrudes that fits inside of the support bar. Example of this is in the pic below.

http://i100.photobucket.com/albums/m8/jamesrea_2006/jamesrea_08/jamesrea09/jamesrea10/006-1.jpg