208 AMAX, 1:12 twist FPS?

Discussion in 'Rifles, Bullets, Barrels & Ballistics' started by dieselgeek, May 24, 2011.

  1. dieselgeek

    dieselgeek Well-Known Member

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    Any one have any numbers on this? I'm looking out of a 20 inch barrel. I saw a thread w/ a 22 inch where he was hitting 1000 w/o effort. gun)


    Thanks in advance

    Ryan
     
  2. LouBoyd

    LouBoyd Well-Known Member

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    You left out an important parameter in your question. That is the air density where you expect to shoot. There are two conditions that need to be met. One is whether the bullet arrives at the target with sufficient velocity to avoid transonic effects. Any ballistics program will answer that if given the muzzle velocity and atmospheric conditions. The other is whether the bullet wil lbe stable over the path and be accurate. Bullet specs and ballistic programs are inadequate to predict that. The reasonable way to find out is to shoot them.
     

  3. dieselgeek

    dieselgeek Well-Known Member

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    Well the main thing I want to know his the MV of the round from a 20 inch barrel. To answer your question

    0.0708
     
  4. trebark

    trebark Well-Known Member

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    1:12 twist may not be sufficient to stabilize the 208grain bullet. Berger recommends 1:10 for their 210VLD but I have seem them stabilize in a 1:11.

    In terms of velocity from a 20" barrel (assuming you could stabilize the bullet), I would think you might be able to get 2400fps.
     
  5. dieselgeek

    dieselgeek Well-Known Member

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    Yeah they pretty much came out of the barrel sideways. gun):D. I'll have to try something else.
     
  6. trebark

    trebark Well-Known Member

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    don't sweat it too much. You can shoot the 190grain VLD or the 178Amax.

    Alternatively, rip the barrel from your rifle and throw it as far as you can, then install a new one that is 1:10 or 1:11 twist and ALL YOUR PROBLEMS WILL BE SOLVED!! :D