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SBR 10.5, 11.5, or 12.5?

Discussion in 'Black Rifle Forum' started by brausso, Feb 27, 2013.

  1. brausso


    Mar 7, 2010
    Puget Sound
    Just picked up an LMT lower today and am sending in my form 1 for my stamp. This is my first go at an SBR. This rifle would be used strictly for range (200 yards or less) and home defense. I have AR's in 16 and 14.5 (pinned) currently.

    I am leaning towards the 10.5 simply because if I'm going to go short, I want to go short. I like this length for cqb.

    What do you recommend and why?
  2. DrtyHarry


    Sep 26, 2007

  3. brausso


    Mar 7, 2010
    Puget Sound
  4. DrtyHarry


    Sep 26, 2007
    Do you plan on suppressing it? I asked the same question a while back when looking into a SBR and this is the best answer I got.

    If you are really going to do it, the 12.5" is probably the best compromise in terms of reliability, handy size, and decent velocity. It can be had in piston or DI. Another poster said you don't gain anything from a piston...not true. The pistons actually shine in an SBR more so than in a full size configuration.

    There are always trade-offs. Are you going to suppress the gun? Important question. The piston will definitely make life easier if going suppressed either way. Downside- pistons tend to have a bit more recoil.

  5. AK_Stick

    AK_Stick AAAMAD

    Jan 20, 2004
    Alaska, again (for now)
    Personally, with a 5.56, I'd never go back to a 10.5

    If I ever buy another SBR, it'll be a 11.5 or 12.5.

    Short is cool, but you just give up too much range and performance with the 7.5-10.5 inch tubes.

    Now a 6.8, or 300 BLK I'd go to 10.5 in a heartbeat.
  6. MrMurphy

    MrMurphy ********* Moderator Moderator Millennium Member Lifetime Member

    Jan 16, 2001
    Buried in the X-files
    What stick said.

    Anything under 12" in a AR tends to get a little funky for truly reliable performance.

    I've got enough time on a variety of SBRs with free ammo to know i'll personally never go under 12" unless it was issued.
  7. KalashniKEV


    Sep 24, 2003
    12.5" gives you the best feel, best reliability, and good velocity.


    10.3/5" and 11.5" I can barely feel the difference without looking at the barrel- and the jump in reliability between 10.5" and 11.5" is real.
  8. kingdong


    Jul 25, 2011
    12.5 any day. Shoot them lots and you'll see.

    Sent from my SAMSUNG-SGH-I317 using Tapatalk 2
  9. utah


    Oct 23, 2002
    Have an M16 with 10.5 223 and 9mm upper and neither has failed to run at anytime...Beta mag dumps included. My opinion...go 10.5".
  10. Keyhole


    Dec 28, 2005
    Houston, TX
    My thoughts exactly. I just switched from a 7 to a 12.
  11. Travclem

    Travclem Badass Member Lifetime Member

    Aug 4, 2008
    Lubbock, TX
    I prefer 10.5" especially since you already have a 16" and a 14.5" carbine. The 12" is a good all around length but since this is a purpose built cqb gun, go short. A 10.5" rifle with most suppressors is the same length as a 16" carbine. Buy a quality upper like LMT or BCM and you should have no reliability issues.

    LMT factory 10.5" SBR

    ETA: I've only put 1,200 rounds through this rifle, but I have had 0 failures.
    Last edited: Feb 28, 2013
  12. txleapd

    txleapd Hook 'Em Up

    Aug 27, 2004
    I have an LMT 10.5 also. It's my work gun that I use for warrant services, building searches, room clearing, etc...

    I went with a 10.5 specifically because it is mainly for CQB type stuff. Before this rifle I used an issued 14.5 rifle, and the difference is huge. All of our SWAT entry guys are running 10.5 rifles too.

    My advice is this.... If you are looking for a CQB gun, get a CQB gun. If you were wanting an all around type rifle, I would agree with going 12-12.5, but you're talking CQB. Use the right tool for the job. You wouldn't want to use a screwdriver if you need a hammer. It can be done, but not nearly as well.

    As far as reliability goes, a quality gun (built that way from the get go) will run.

    Since you're talking CQB, the barrel length won't effect ballistics enough to matter at the distances you intend to use it. I hope you don't plan on 200+ yards shots in CQB. You've got other rifles for that.


    Posted using Outdoor Hub Campfire
  13. Big Bird

    Big Bird NRA Life Member

    Aug 7, 2003
    Louisville KY
    I have a 10.5" LMT upper SBR. I have no issues. When I first got it it short stroked. Called LMT and turns out I was using a H2 buffer and they recommend a Standard Carbine Buffer with their upper. Made the switch to the Std buffer and its been flawless over 1,000 rounds since.

    You won't have issues with ammunition terminal performance inside of about 120 yards with an SBR. Beyond 175 yards all guns--even a 20" rifle drops below the velocity required for M193 or M855 to fragment in tissue. Other ammunition may do better.
  14. Mayhem like Me

    Mayhem like Me Semper Paratus

    Mar 13, 2001
    Not a chance
    My 10.5 piston runs 100% so does my DI Colt. Build what you want .

    10.5 is a great size for a dedicated entry gun. I like 12.5 as a patrol rifle since it gives a little more range and is managable in CQB.
  15. WoodenPlank

    WoodenPlank Who?

    May 15, 2010
    NW Florida
    I have a 10.5", and I have been very happy with it. My LMT upper is easily minute-of-man accurate at 300 yards (even with crappy ammo and nothing more than an Aimpoint), and has been boringly reliable with a BCM bolt group and H2 buffer.

    If I had to do it all over again, though, I probably would have gone with 11.5" (Factory Colt Commando) for the slight increase in velocity and better reliability.
  16. mjkeat


    Jun 17, 2009
    I've only ran a couple SBRs and the 12.5" versions seemed to work more reliably.
  17. Cole125

    Cole125 Silver Member

    Apr 5, 2008
    Far West, USA
    If you going to all the trouble to get a SBR, get the 10.5!
  18. Clusterfrack


    Apr 26, 2012
    Pacific NW
    Like Woodenplank, my LMT Mk18 10.5" has been 100% reliable, both suppressed and unsuppressed. I've done just fine at 300 yards with it too.
  19. AK_Stick

    AK_Stick AAAMAD

    Jan 20, 2004
    Alaska, again (for now)
    I never had any issues reliability wise with my rifles.

    I simply wanted the increased velocity and energy of the longer barrel. (And since I can take my upper to work with me, possible real life usage weighed in)
  20. txleapd

    txleapd Hook 'Em Up

    Aug 27, 2004
    If I were king, all of our patrol rifles would have 12.5 barrels.

    Posted using Outdoor Hub Campfire