Help with bullet sorting!!!

[tpberry]

Recently I bought 2 Davidson seating depth checkers to help sort my bullets. I started using 2 of the gauges to measure from the ogive to the last part of the bullet touched by the rifling. My problem is that every bullet measures different. Sometimes as much as .01, making it impossible to sort them. When sorting I had 10 different piles. I tried using only 1 of the gauges and the same thing happened. After this I tried using the hornady comparator and I only got 3 piles. So my question..Am I able to use the Davidson gauges for VLDs? If it helps I'm measuring .338 300grn OTMs

 

[Terry]

I use two Hornady comparators facing each other on my digital calipers.
It works well.

 

[memo43]

I use the hornady ones, after establishing a tolerance I go .003 as a baseline.
I normally get 4-5 piles and the random ones get put in there own piles and arenuse to foul the barrel etc etc. It really comes down to what your willing to accept as a tolerance.
The reason you get different piles with different tools is based on the manufacturing tolerances.
Use what you feel the most comfortable with and go with it.
Once you have your piles,, keep them separate an only load from one until you run out and move to the next one.
I learned that it's more important to practice shooting than trying to squeeze every once of accuracy out of the load development.
Prac prac prac and more practice

 

[JamesnTN]

I use the hornady ones, after establishing a tolerance I go .003 as a baseline.
I normally get 4-5 piles and the random ones get put in there own piles and arenuse to foul the barrel etc etc. It really comes down to what your willing to accept as a tolerance.
The reason you get different piles with different tools is based on the manufacturing tolerances.
Use what you feel the most comfortable with and go with it.
Once you have your piles,, keep them separate an only load from one until you run out and move to the next one.
I learned that it's more important to practice shooting than trying to squeeze every once of accuracy out of the load development.
Prac prac prac and more practice

.003 is a lot when sorting I sort my bullets with two comparators as well and sort within .001 example if bullet measures .780 I keep it at .780 and .7805 next batch is .781-.7815 and so on.

 

[BillPa]

I use two Hornady comparators facing each other on my digital calipers.
It works well.

Same here, one on the ogive, one on the heel.

The one on the heel eliminates any inconsistencies of the base in the measurement. They also allow consistent placement in the caliper.

Bill

 

[deadwooddick]

… The reason you get different piles with different tools is based on the manufacturing tolerances

+1

 

[kyreloader]

Base to bullet ogive seems to be the most important measurement for bullet sorting (Bryan Litz and others), so that has been the method I have been using to sort.

 

[JamesnTN]

Base to bullet ogive seems to be the most important measurement for bullet sorting (Bryan Litz and others), so that has been the method I have been using to sort.

Is it base to ogive or base to where seater stem makes contact?

 

[SDDasher]

"Is it base to ogive or base to where seater stem makes contact?"

Latter; if you want consistent seating depth of your bullets. BGC (Bob Green Comperator) will sort bullets for this measurement.

 

[Joe Salt]

Kyreloader Base to Ogive is the most consistent measurement of a bullet, Bryan is in the market to sell you bullets! I use two bushing to sort my bullets, Its the fat and skinny ones the will kill you at long range. Pressure Difference!

Joe Salt

 

[Joe Wade]

Here is a good Eric Cortina video that shows some of the different comparators and how they work.
He also has a good one on the Bob Green comparator.

https://www.youtube.com/watch?v=-ZWrr1_IPu8

 

[tpberry]

Problem fixed. I was thinking that the. 338 300gr OTMs were bottoming out in the guage before it would contact the ogive. So...I drilled the comparator a little deeper. Now my measurements are close

 

[mikecr]

Has anyone done an actual test to validate supposed bearing length variance as affecting anything?

 

[Joe Salt]

Mikecr: If you get bullets with over 30 Thou. difference in bearing lenght you will see a difference in seating depth!

 

[barefooter56]

tpberry,
Davidson bullet tools are made to work with standard tangent ogive bullets only. As you found out. The most common mistake out there is using one comparator to "check" another comparator. They are ALL different. Even from the same manufacturer there can be differences due to machining tolerances. Its a "comparative measurement" which means you are comparing one bullet to another bullet. NOT one comparator to another. Pick ONE and use it. Anything else can lead to alcoholism or madness ! lol !!
PS, even the amount of pressure you apply to the calipers along with measuring a bullet multiple times will affect your measurements also. Try to be as consistant as you can with the first and do the second 2 times at most.
PPS, ZERO the caliper across the comparator first before starting your measuring process and CHECK that the caliper is still zeroed after doing a number of measurements as you go along.
Hope this helps guys!

 

[mikecr]

Mikecr: If you get bullets with over 30 Thou. difference in bearing lenght you will see a difference in seating depth!

No, bearing has no affect to seating depth.
I hope that's not the reason for this bearing comparison industry..

I figured at first bearing comparison was for MV ES. But I tested a normal spread and there was no difference in MV due to bearing variance. So then I thought BC. But bearing means nothing to overall BC(calculated), as bearing variance in itself holds least affect to drag. As long as the flow mode(laminar/turbulent) remains the same, it just doesn't matter.

I discontinued bearing checks a long time ago, focusing purely on ogives/meplats. And it just surprises me that so many still busy themselves with bearing guesitimations(due to unqualified base & ogive contributors).

 

[JHardy]

+1 on Bob Green's tool.

Jim Hardy

 

[tenring]

I use the Davidson nose pieces together also. Boat tails are a little tricky to check consistently. I put each in a marked plastic cup, sort 500 at a time. I will then take the 2 piles most alike and combine them to make one batch. The others are used for practice or sighters. But to be honest, I cannot say that I see much difference even if the bearing lengths are .010 apart.

 

[Canadian bushman]

Has anyone done an actual test to validate supposed bearing length variance as affecting anything?

I did a test comparing .005 variance in bearing surface to .002 variance in bearing surface length with the 215 hybrids, not base to ogive, and found the results to very slightly favor the sorted bullets. I mean very slightly, easily lost in the noise. Pointing seemed to hold a much larger contribution to controlling vertical than bearing surface.

For the level i shoot at i could probably get away with sorting within .005" for this bullet, or even splitting a box into two groups - low/high.

Another thing to consider when sorting by bearing surface is not the tolerance you give yourself in .xxx" of inches, but that number as a percentage of area of the bearing surface.
IE if you are sorting 338 300 grain bullets and 243 60 gn bullets into .001" groups, you are sorting the 338 bullets to a much finer degree.

 

[Ringostar]

I use two bushing to sort my bullets, Its the fat and skinny ones the will kill you at long range. Pressure Difference!
I've tried the 2 hornady comparitors on my caliper. It didn't take long to give up on it. The holes aren't perfectly true, so I got various readings. I like Joe's idea here about checking the outside through bushing, but how true are the holes through the bushing? Oops, I didn't mean to add my line in with the quote. Not sure how to fix it without starting over.