SBR accuracy? - AR15.COM

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Posted: 8/29/2014 2:18:22 PM EDT

What kind of accuracy are you getting out of your SBR's?

My 11.5" BCM BFH absolutely sucks with everything I've tried in it, I'm talking 5" groups at 100 yard suck. I don't expect sub-moa with the thing but I would think it should be a little better than that, the 5"ers were some of the better ones. The barrel and crown look fine.

I was thinking it had something to do with the 1-6 scope so I pulled the 5-20 razor off my AI .308 and it wasn't any better.

Ammo tried. All 75-77gr.

FGMM
Black hills MK262
Privi
Hornady match
Hornady steel match
Winchester 69gr. Match
A shitload of different hand loads.

Everything is torqued properly.

Posted: 8/29/2014 2:22:36 PM EDT

[#1]

Something is wrong... It should group as well as any other 16''+ barrel all else equal
Try some plain old M193 and see how you do.

Posted: 8/29/2014 3:00:24 PM EDT

[#2]

My 10.5" PSA with a 4x scope grouped 2-3 MOA at 100 yards.

Posted: 8/29/2014 3:01:34 PM EDT

[#3]

We are getting sub MOA with our barrels....and we guarantee sub MOA using match grade ammo.

I'm not the best shot but here is a group I shot at 100 yards with our 12.5" Mid-length barrel (Govm't contour), 69 Gr Federal Gold Medal.

I also get sub MOA with Geco 55 Gr and Federal 77 Gold Medal Match.

I've got other customers reporting sub MOA with all of our other length barrels as well. Including the 10.5's and 11.5's.

More info at: http://micromoa.com

and https://www.facebook.com/MicroMOA

Posted: 8/29/2014 3:34:29 PM EDT

[#4]

Barrel length should not affect "accuracy" as much as it would affect the performance of the round at range (drop, energy, etc).

Posted: 8/29/2014 3:36:42 PM EDT

[#5]

Did BCM build it, or is it just one of their barrels?

If BCM built the upper, I would contact them. Something is wrong with that.

Posted: 8/29/2014 3:41:28 PM EDT

[#6]

Quote History

Quoted:
Did BCM build it, or is it just one of their barrels?

If BCM built the upper, I would contact them. Something is wrong with that.

View Quote

Just the barrel. I'll try to contact them again. Maybe they'll answer the phone or email after the holiday.

Posted: 8/29/2014 3:51:55 PM EDT

[#7]

Since they only built the barrel, I would take it apart and put it back together if you have the tools for the job. It's possible something is going on with the barrel nut / handguard installation.

Posted: 8/29/2014 3:57:23 PM EDT

[#8]

Quote History

Quoted:
Since they only built the barrel, I would take it apart and put it back together if you have the tools for the job. It's possible something is going on with the barrel nut / handguard installation.

View Quote

I do have the tools, everything's on there correctly I did it twice, the KMR rail is stupid easy.

It looks pretty though.

Posted: 8/29/2014 6:36:57 PM EDT

[#9]

My 11.5 BCM LW CL has consistently given me sub MOA groups with tuned handloads and quality bullets

Posted: 8/30/2014 9:30:38 PM EDT

[#10]

I'm with everyone else. Something is up. I shoot an 11.5" BCM BFH too and it's extremely accurate out to 300 yards. Haven't gone out past that but I think it's the perfect length. Amazing accuracy and light weight. Very comfortable. Maybe check the chamber for scratches or gouges? Any type of erosion or machining mistake.

Posted: 8/31/2014 4:03:01 AM EDT

[#11]

I cleaned everything up yesterday, removed the barrel retorqued the barrel nut. The XM193 shot the best at just over 3 moa everything else was the same at 100. There was a kid next to me shooting a ruger 10/22 and our groups looked about the same, his was a lot quieter though.

I'm guessing there's something wrong in the chamber as I've been getting a lot of stuck cases as well.

I'll see what BCM says on Tuesday hopefully.

Posted: 8/31/2014 6:10:54 AM EDT

[#12]

Quote History

Quoted:
I cleaned everything up yesterday, removed the barrel retorqued the barrel nut. The XM193 shot the best at just over 3 moa everything else was the same at 100. There was a kid next to me shooting a ruger 10/22 and our groups looked about the same, his was a lot quieter though.

I'm guessing there's something wrong in the chamber as I've been getting a lot of stuck cases as well.

I'll see what BCM says on Tuesday hopefully.

View Quote

Are you having any misfeed issues? When I built my first upper it had misfeeds and shot terribly. I bet you have probably checked, but with my first build upper it turned out the feed ramp had not been rounded and the corners were shredding the projectiles as they were pushed toward the chamber. I used a round file to smooth out the ramps, and it worked just fine and was much more accurate.

Posted: 9/1/2014 9:49:07 AM EDT

[#13]

No, the ramps look good.

Quote History

Quoted:

Are you having any misfeed issues? When I built my first upper it had misfeeds and shot terribly. I bet you have probably checked, but with my first build upper it turned out the feed ramp had not been rounded and the corners were shredding the projectiles as they were pushed toward the chamber. I used a round file to smooth out the ramps, and it worked just fine and was much more accurate.

View Quote View All Quotes

View All Quotes

Quote History

Quoted:

Quoted:
I cleaned everything up yesterday, removed the barrel retorqued the barrel nut. The XM193 shot the best at just over 3 moa everything else was the same at 100. There was a kid next to me shooting a ruger 10/22 and our groups looked about the same, his was a lot quieter though.

I'm guessing there's something wrong in the chamber as I've been getting a lot of stuck cases as well.

I'll see what BCM says on Tuesday hopefully.

Are you having any misfeed issues? When I built my first upper it had misfeeds and shot terribly. I bet you have probably checked, but with my first build upper it turned out the feed ramp had not been rounded and the corners were shredding the projectiles as they were pushed toward the chamber. I used a round file to smooth out the ramps, and it worked just fine and was much more accurate.

Posted: 9/1/2014 11:20:52 AM EDT

[#14]

Quote History

Quoted:
I cleaned everything up yesterday, removed the barrel retorqued the barrel nut. The XM193 shot the best at just over 3 moa everything else was the same at 100. There was a kid next to me shooting a ruger 10/22 and our groups looked about the same, his was a lot quieter though.

I'm guessing there's something wrong in the chamber as I've been getting a lot of stuck cases as well.

I'll see what BCM says on Tuesday hopefully.

View Quote

pull bbl , polish chamber. AFTER you talk to BCM. You check OAL of round to chamber size?

Posted: 9/1/2014 6:10:07 PM EDT

[#15]

I would say something is wrong. My DD barreled franken SBR can consistently ring 2/3 IPSC steel at 200+ w/ a 4moa aimpoint T1. As long as the bullet doesn't come apart mid flight(1969 surplus m196 tracer).

I haven't shot for group sizing though as I have no magnified optics.

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