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Barrel twist and other advice needed

Discussion in 'GATE NFA/Class III' started by C6drvr, Jun 15, 2012.

  1. C6drvr


    Apr 8, 2007
    West Texas
    I'm looking to build a SBR. We're an 07/02 so we can go ahead with the work at will, but we're unsure what barrel length is best with what twist rates, etc...

    I'm thinking a 10.5" barrel is what we want, but if the collective thinks we can go with shorter (8.5" maybe) we would probably do that.

    My questions are this:

    What would be the best twist rate in 5.56/223 for a 10.5 and 8.5" barrel?

    What would be the best twist rate in a 300blackout in the 10.5 and 8.5" barrels.

    and finally, is the 8.5" barrel in either caliber going to be so short it kills velocity and affects accuracy because of it?

    Thanks all.
  2. Zak Smith

    Zak Smith 3Gunner Millennium Member

    Aug 25, 1999
    Fort Collins, CO, USA
    Anything shorter than 10.5" requires more work to get it working right. The common 10.5 - 12.5" formats work better and are easier on the parts. Twist rate same as a non-SBR for the same bullet weights you want to shoot.