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# Sort by bearing length and by weight?

#1
02-01-2012, 12:47 AM
 Gold Member Join Date: Mar 2008 Location: N. Central Indiana Posts: 608
Sort by bearing length and by weight?

I'm trying to fine tune my reloading. I've purchased the Buhay tool and I'm in the process of sorting my bullets into .001" groups. Do I need to sort by weight too, or is it not necessary? If yes, then what weight variance should each group have?

FWIW, it's for one of Kirby's 7mm AM's.

Is .001" groupings of the bearing surface getting too anal?

I went back thru the sub-forum to 2007, and saw that bearing surface was more important than weight, but no numbers or % was given for determining how to group the bullets that were sorted.
#2
02-01-2012, 05:41 AM
 Platinum Member Join Date: Jan 2007 Location: PA Posts: 1,324
Re: Sort by bearing length and by weight?

What brand bullets? Some are more consistent than others.

I sort them out and use any that exceed 3 grains difference for sighters.

Bearing surface measurement is more important for good accuracy. Again, I cull out those that exceed .001".
#3
02-01-2012, 09:09 AM
 Platinum Member Join Date: Nov 2005 Location: Texas Posts: 1,845
Re: Sort by bearing length and by weight?

I have used the Buhay tool for many years and use SMK's only and I do not sort by weight. Found that it was a waste of time..
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#4
02-01-2012, 12:17 PM
 Gold Member Join Date: Mar 2008 Location: N. Central Indiana Posts: 608
Re: Sort by bearing length and by weight?

Wildcat 7mm bullets. I arbitrairly set the indicator at .000" and have groups of bullets that are as follows: -.002", -,001", .000", +.001", +.002", +.003"

There could be a varience of .001" within those groups, if a bullet was -.0004" or +.0004" from those numbers, it went into the same group. The biggest groups are .000" thru. +002", but the other groups aren't that far behind in numbers. I've only sorted 300 bullets so far.

I randomly grabbed bullets out of the groups and re-measured, and my measurements didn't change, so I'm confident that my measuring procedure is correct and repeatable.

I have 175g SMK's and 180g Bergers that I will be measuring too.
#5
02-01-2012, 12:39 PM
 Platinum Member Join Date: Aug 2003 Location: NC, oceanfront Posts: 4,222
Re: Sort by bearing length and by weight?

I don't think bearing variance could be proven to make any difference at all.
And if your measuring base to nose, then base length would need to be accounted for differently.
Second, unless you account for each drag component, summed to contribute to BC, you could not know if bullets match in BC regardless of individual measures.
Third, without RADAR or atleast an accoustic chronograph, you cannot measure the tiny bullet engraving length affects to MV.

And as far as weight, if your bullets vary in weight enough to affect anything, you are using horrible bullets. All parameters would then be suspect so rake em into a trash can.
Pull out the wallet and buy the best bullets you can.
#6
02-01-2012, 01:27 PM
 Gold Member Join Date: Mar 2008 Location: N. Central Indiana Posts: 608
Re: Sort by bearing length and by weight?

Mikecr, then what bullets do you suggest (that are available)?

If you knew what a Buhay tool was, then you wouldn't have made some of the other comments.
#7
02-01-2012, 02:07 PM
 Platinum Member Join Date: Nov 2005 Location: Texas Posts: 1,845
Re: Sort by bearing length and by weight?

Quote:
 Originally Posted by Mikecr I don't think bearing variance could be proven to make any difference at all. For one, your datums aren't qualified as consistent(ogive radius, base angle). And if your measuring base to nose, then base length would need to be accounted for differently. Second, unless you account for each drag component, summed to contribute to BC, you could not know if bullets match in BC regardless of individual measures. Third, without RADAR or atleast an accoustic chronograph, you cannot measure the tiny bullet engraving length affects to MV. And as far as weight, if your bullets vary in weight enough to affect anything, you are using horrible bullets. All parameters would then be suspect so rake em into a trash can. Pull out the wallet and buy the best bullets you can.

I hope you are kidding. Len has told me not to put cold hard data out to make people look bad but for God's sake do the due diligence before you type..... Find out about the subject before making a formal statement. I am sorry I could not let this statement go unaddressed.

Bearing surface equals pressure. I have posted paragraphs about this in the past and I am sure others have as well.

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The Truth Is Not Always Good For Business!!

Last edited by Boss Hoss; 02-01-2012 at 02:38 PM.

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