Ar-15 barrel twist

Discussion in 'Gunsmith shop' started by Jed, Dec 27, 2014.

  1. Moving to the next step in my home-brew AR-15. I am finding some differing information on the effect of barrel twists on .223 vs. the 5.56. Some are of the opinion that the slightly heaver ball on the 5.56 calls for a barrel twist of 1 to 7, while the .223 does well with a twist of 1 to 9. Some go the middle ground and recommend a 1 to 8 in order to split the difference. Granted the 5.56 can have higher chamber pressure than the .223 and that would have to be addressed but what have people experienced with the various barrel twists on the 5.56 vs the .223?
  2. Asher1

    Asher1 Member

    If you building a budget AR then go with what ever barrel you get the best deal on... If you building a higher end rifle, then I would prefer the 1:8...

    Since your building one, have you looked at the 300aac (or blackout) round?? Same mags, same bolt, springs, etc, just a different barrel chamber and round..

  3. Johnny_B_Goode

    Johnny_B_Goode Member

    If you are going to shoot 55gr and up ammo 1:7 twist will be your best option. Chances are if you are shooting 55gr ammo you are fending off zombie cans. Zombie cans are slow moving, so it doesn't matter if you miss a couple.

    When you pay $20 a box or more for ammo it is going to be a heavier and longer bullet that will flatter the 1:7 twist. If you reload the 75gr BTHP bullets will really appreciate the 1:7 twist.
  4. bscar

    bscar Supporting Member

  5. greg_r

    greg_r Lifetime Supporter

    Twist has not much to do with the weight of the bullet as it does the length of the bullet. The weight is only relevant because the heavier bullets are generally longer. I like the all copper bullets on deer because the bullets perform better. Copper bullets are long for their weight.

    That said if you are shooting conventional lead core bullets 40 to about 70 grains 1/9 will be fine. Heavy conventional bullets or all copper bullets heavier than about 50 grains needs a 1/7.
  6. Think1st

    Think1st Supporting Member