close

Privacy guaranteed - Your email is not shared with anyone.

Twist Rates & Bullet Weights

Discussion in 'The Powder Keg' started by Logansdad, May 12, 2002.

  1. Logansdad

    Logansdad Guest

    I was told that the Viet Nam round was a 70 grain bullet exiting a 20 inch barrel with a 1 turn in 12 or 14 inch twist rate. I was also told that the SS109 round is a 62 grainer optimized for a 20 inch barrel with a 1 turn in 7 inch twist rate. I was also told that the 55 grain projectile was optimal for a 1 turn in 9 inch twist and what the Military was going to standardize upon for regular line troops.
    What is the real story ?
     
  2. Logansdad

    Logansdad Guest

    Oh yeah...the 70 grainer wasn't supposed to stabilize....allowing it to "Keyhole" or tumble.
     

  3. MikeC

    MikeC G&G Newbie

    96
    0
    The M193 round, used in Viet Nam, which is a 55gr bullet uses a 1 in 12 twist. The new SS-109/ M-855 62 gr bullet uses a 1 in 7 twist. The 1 in 9 twist will handle both weights and is a compromise for civilian rifles. I have heard that the original M-16 had a 1 in 14 twist, but that was marginal and was changed to the 1 in 12 twist. Hope that helps.
     
  4. Logansdad

    Logansdad Guest

    I need to research it more :hmmm: