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  #31  
Old Today, 07:31 AM
Mike Clark is online now

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Simplest way to think about it:
For accuracy you want the slowest twist that will stabilize a given bullet.
Anything slower and the bullet is understablized.
Anything faster and the bullet's out of balance affects the flight more.

Atmospheric conditions do affect it. So some fudge factor is built in.
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  #32  
Old Today, 08:05 AM
David Valdina
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Adding to Mike's post...

Mike writes, Simplest way to think about it: For accuracy you want the slowest twist that will stabilize a given bullet. Anything slower and the bullet is under stabilized.
Anything faster and the bullet's out of balance affects the flight more.

Let me add a bit to this correct statement. If you err on too fast, you seldom have big problems. If you err on too slow, you can have big problems. And if you are shooting long distance, you want stability over the entire range.
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  #33  
Old Today, 08:28 AM
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Quote:
Originally Posted by David Valdina View Post
Mike writes, Simplest way to think about it: For accuracy you want the slowest twist that will stabilize a given bullet. Anything slower and the bullet is under stabilized.
Anything faster and the bullet's out of balance affects the flight more.

Let me add a bit to this correct statement. If you err on too fast, you seldom have big problems. If you err on too slow, you can have big problems. And if you are shooting long distance, you want stability over the entire range.
Mr David that is a very nice addition.

One aspect of over stabilized is the bullet can fly tip up. You can see this when throwing a football.

Also bullet spin doesn't reduce downrange with velocity as a direct relationship. Velocity drop but bullet spin rate stays pretty constant.
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  #34  
Old Today, 08:56 AM
David Valdina
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Bullet RPM over distance etc.

Yup, I have read that bullet RPM is pretty much a constant. The centerfire crowd drives their bullets as fast as they can for accuracy (generalized statement) So considering velocity gets slower the minute the bullet leaves the barrel, at longer ranges you will have considerably less velocity. A long for caliber bullet may need speed to be stable and when the speed drops off, may loose stability. Not related to the spin but to the speed. Easy way to test if you reload is to load some long for caliber bullets at very low velocity and shoot at 100 yards until you start to see the holes in the target elongated, indicating the bullet is not hitting point on. A sideways traveling bullet is not apt to give high accuracy. One other comment, when hunting in the woods or places where your bullet might hit a branch on the way to the animal, a faster twist will resist deflection a wee bit better than a slow twist. And heavy constructed will resist coming apart prematurely.
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  #35  
Old Today, 10:49 AM
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Quote:
Originally Posted by David Valdina View Post
The centerfire crowd drives their bullets as fast as they can for accuracy (generalized statement)
I am definitely with you on all of this.

I am a proponent of the OCW Method. It essentially identifies the highest velocity accuracy node and quickly narrows down the range of that nodes charge weight.

That said BC trumps MV down range.
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