what effect does barrel twist have?

Discussion in 'The Basics, Starting Out' started by rocknwell, Aug 6, 2011.

  1. rocknwell

    rocknwell Well-Known Member

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    Hello, can i get some help on understanding how different ratios of barrel twists affect the flight of bullets? does a smaller ratio (faster spinning bullet) go straiter than a larger ratio (slower spinning bullet)? what effect do these have on BCs? I'm looking to get a rifle in either 7mm rem mag or .308 and i'd like to know what type of barrel twists i should be looking for/what not to get. Thank you!

    Micah
     
  2. Coyboy

    Coyboy Well-Known Member

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    the longer/heavier bullets require faster twist rates for the given bore, than the short stubby lighter bullets.

    If your getting a factory rifle your choices are pretty slim.

    If your getting a custom tube tell your smith what bullets you plan to shoot and he will get the proper twist.

    If you need more try the search function or google.

    one twist is no more accurate given that the bullet matches the twist.
     

  3. rscott5028

    rscott5028 Well-Known Member

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    I beleive Jim answered your question. He can also build you exactly what you want/need.

    But, here's more info.

    It's like a nice spiral footbal pass vs a wobbly throw. If you spin it too fast, it doesn't buy you anything while too slow will reduce your accuracy.

    Here's a link to some good rule of thumb numbers...
    Welcome to Shilen Rifles, Inc.

    Sometimes the bullet makers have a recommended twist rate as seen here...
    Berger Hunting Bullets

    Here's an online tool for calculating the ideal theoretical twist rate...
    JBM - Calculations - Stability

    Hope this helps.
    Richard
     
  4. rocknwell

    rocknwell Well-Known Member

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    Thanks guys i appreciate it. I will look into it.
     
  5. roninflag

    roninflag Well-Known Member

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    for me barrel quality is way more imporatant than twist rate.
     
  6. MHO

    MHO Well-Known Member

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    rscott and coyboy explained it well. It all comes down to stabilizing the bullet which will make you more consistent. Barrel twist will affect it depending on the bullet you are using.
     
  7. 270winshort

    270winshort Well-Known Member

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    just to add on your question on how it affects bc the bullet has a bc the twist rate does not affect the bc of the bullet, provided you have the proper twist rate for the bullet that you are going to shoot, to fast a twist rate is better than to slow, IMO, so it is better to get a barrel with a slightly faster twist than one slightly slower
     
  8. rocknwell

    rocknwell Well-Known Member

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    thanks guys i appreciate it. that helps me understand things better.