168 vldh base to ogive variance

kkammenzind

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Joined
May 25, 2008
Messages
262
Location
Washington
I was having very inconsistant results during load development. I have always had good results with the vld's.
I measured 80 bullets with a comparator and found them to be from .702 to .714. All from the same lot.
That seems like a huge disparity. Can someone share what tolerance is normal/acceptable?
Thank you-KK
 

lgordee

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Joined
Jul 10, 2012
Messages
433
I was having very inconsistant results during load development. I have always had good results with the vld's.
I measured 80 bullets with a comparator and found them to be from .702 to .714. All from the same lot.
That seems like a huge disparity. Can someone share what tolerance is normal/acceptable?
Thank you-KK
Assuming you are speaking of Berger's. Within the same lot it is rare I would find two in a hundred more than + or - .001". Doesn't seem right from my experience. Now different lots will vary that much. With another brand I have had as many as 8 different piles from the same lot.
 

Mikecr

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Joined
Aug 10, 2003
Messages
5,246
Location
NC, oceanfront
You don't know the significance of deviations from BTO measure.
The ultimate goal here is in matching BC. There is no other other real gain.
Well, drag contributing to BC is separate for base, and bearing, and ogive datum, included in BTO. Each having different contributions, and you haven't separated them, nor considered other attributes of the same bullets to calculate overall drag. Things like ogive radius, nose length, meplat diameter, are missing.

For all you know, the bullets deviating in BTO also happen to match the BC mean of your lot. And some bullets matching in BTO might actually deviate from BC mean of the lot.
So you do not have enough information from BTO only to act on.

I'm sure you want to improve things. But doing things you don't understand(possibly), because this mob does things it doesn't understand, is not the way to improve things. It's just silly shortcuts to nothingville.
My advise: Buy good bullets & have faith in them.
 

kkammenzind

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Joined
May 25, 2008
Messages
262
Location
Washington
All I asked was if that was normal and acceptable. I thought that Ipurchased good bullets.
Thanks for asuming what I don't undefstand.
 

Rhovee

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Joined
Jun 29, 2017
Messages
996
That’s Quite a bit for Bergers. Call them up and see if they will switch them out.
 
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