twist rate help

Discussion in 'Long Range Hunting & Shooting' started by supercrossbmx69, Feb 9, 2011.

  1. supercrossbmx69

    supercrossbmx69 Well-Known Member

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    ok ive been stuck on this question for a while and dont even really know how to ask it but im going to try, for a 30 cal. 240 gr SMK the recommended twist is 1-9 so if i bought a 1-9 twist barrel and dident like the bullets what would be the outcome if i bought matrix or berger 210 grain bullets where theyre twist rate is 1-11 and switched to them? would it kill accuracy? thanks for your help guys.
     
  2. groper

    groper Well-Known Member

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    Whilst i cannot say ive ever shot 210`s from a 9 twist, theory says that with match quality bullets you would barely notice the difference in accuracy from the higher twist rate alone. A lower stability factor is better, but your really starting to split hairs with this line of thinking.

    For example, i shot 155gr palma match bullets from my .308 which happened to have 10twist barrel so i could also shoot the heavier bullets aswell. The preferred twist for these competition bullets in match rifles is 1:13. The bullets still shot exceptionally well for me, many groups were sub 1/4MOA when i did my part.

    Benchrest shooters looking for every last ounce of accuracy will nearly always choose the slowest twist possible for that bullet, but these guys are chasing every last 0.1MOA they can get. So i don think its worth worrying about when considering a long range hunting application. You will get far more dispersion from many other factors you have to deal with. This means you will effectively not notice its effects.
     

  3. ubettcha13

    ubettcha13 Well-Known Member

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    A tighter than optimum twist will hinder your ability to get your highest velocities. Too tight a twist will cause bullet blow ups in ultra high velocity rounds (not going to be an issue here) A good thing is the extra RPM of the bullet will cause a more dramatic effect on a tissue target
     
  4. rscott5028

    rscott5028 Well-Known Member

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    Notwithstanding benchrest accuracy concerns as described above, some people beleive that overstabilizing is better than understabilizing.

    You can always back down from max velocity to avoid shreading bullets, but you'll have to rebarrel to get a faster twist.

    If you think speeding up your bullet in a slow twist barrel will increase the rpm enough to stabilize it, then check your math. A few hundred fps does nothing for rpm compared to 1 in 10" vs 1 in 9".

    This is my understanding/opinion from a lot of reading and a little experimentation. But, you may want a more qualified source than me.