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Rotational velocity vs wound severity

 
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  #15  
Old 10-26-2012, 09:40 PM
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Re: Rotational velocity vs wound severity

What if you throw in a gain twist barrel.....? There's a monkey wrench

Looking forward to seeing a baseline, & results of your testing.
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  #16  
Old 10-26-2012, 09:57 PM
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Re: Rotational velocity vs wound severity

Quote:
Originally Posted by winmag View Post
What if you throw in a gain twist barrel.....? There's a monkey wrench

Looking forward to seeing a baseline, & results of your testing.
That's a good one. Seriously though, the rotation is still whatever the velocity x twist is as the bullet leaves the barrel......Rich
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  #17  
Old 10-26-2012, 10:11 PM
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Re: Rotational velocity vs wound severity

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Originally Posted by elkaholic View Post
That's a good one. Seriously though, the rotation is still whatever the velocity x twist is as the bullet leaves the barrel......Rich
Very true for rpm.

However "IF" a tight twist tends to grind up lighter/shorter bullets, & a gain twist can sometimes "Ease" or "Aleviate" the grinding effects but still have a faster rpm at exit, there may be some Merritt to the jacket stress vs twist ratio. Hmmmm sounds too scientific not to be a monkey wrench hahahaha

This is like rocket surgery... I love it
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  #18  
Old 10-26-2012, 10:16 PM
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Re: Rotational velocity vs wound severity

Quote:
Originally Posted by winmag View Post
Very true for rpm.

However "IF" a tight twist tends to grind up lighter/shorter bullets, & a gain twist can sometimes "Ease" or "Aleviate" the grinding effects but still have a faster rpm at exit, there may be some Merritt to the jacket stress vs twist ratio. Hmmmm sounds too scientific not to be a monkey wrench hahahaha

This is like rocket surgery... I love it
But gain twist also makes larger grooves in the jacket by virtue of the fact that that the angle changes as the bulllet progresses, which causes GREATER loss of jacket integrity........Rich
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  #19  
Old 10-26-2012, 10:18 PM
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Re: Rotational velocity vs wound severity

The modified Point mass trajectory calc. includes rpm. It's neither linear or constant but the rpm loss seems to be about 20% over a 100yrds for a 168gr 7mm

JBM - Calculations - Modified Point Mass Trajectory

click on the link and then hit calc at the bottom
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Keep in mind the animals we shoot for food and display are not bullet proof. Contrary to popular belief, they bleed and die just like they did a hundred years ago. Being competent with a given rifle is far more important than impressive ballistics and poor shootability. High velocity misses never put a steak in the freezer.

Joe
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  #20  
Old 10-26-2012, 10:24 PM
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Re: Rotational velocity vs wound severity

Quote:
Originally Posted by Joe King View Post
The modified Point mass trajectory calc. includes rpm. It's neither linear or constant but the rpm loss seems to be about 20% over a 100yrds for a 168gr 7mm

JBM - Calculations - Modified Point Mass Trajectory

click on the link and then hit calc at the bottom
I'm only seeing about 2.3 % ??
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  #21  
Old 10-26-2012, 10:54 PM
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Re: Rotational velocity vs wound severity

1000yrd rpm-166249
Muzzle rpm-212793

166249/212793=0.781

1 - 0.781=0.219

100%*0.219 =21.9%
__________________
Keep in mind the animals we shoot for food and display are not bullet proof. Contrary to popular belief, they bleed and die just like they did a hundred years ago. Being competent with a given rifle is far more important than impressive ballistics and poor shootability. High velocity misses never put a steak in the freezer.

Joe
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