Bullet Bearing Surface Length Question(s)

[royinidaho]

'nother question....

If a person was going to make their own, not that I'm going to, what would be diameter of the hole be for say the 270 cal?

I measure the hole in the "nut" thing from sinclair at 0.260". This seems to get me too far down the point/ogive and boat tail.

The bullet front end has to be deforming a bit as it grows in length when its shrunk the 0.006" from 284 to 277.

 

[milanuk]

the downside is that if you think you are sorting by .001" you are kidding yourself. in reality it might be as good as .002"-.003"
The Buhay unit is slower and much more expensive but is capable of sorting to .001"

I'm curious... why do you believe the caliper method is so much less accurate? Is this based off of re-sorting bullets originally sorted by the caliper, using the Buhay tool? Do you have any guesses why a set of dial calipers that read to 0.001" would be less accurate than a dial indicator that reads to 0.001"?

I'm curious mainly because I have the twin stoney point set up - actually, one side is a Sinclair insert, way nicer, tapered hole, no 'rocking' like w/ the Stoney Point/Hornady inserts with their radiused hole) and have been considering the Buhay tool.

When y'all say the caliper method is faster... how much faster (best guess)?

TIA,

Monte

 

[PrecisionRifleBlog]

I wrote an article that has a brief explanation of bearing surface, how to measure true bearing surface (different from base to ogive), and the bearing surface variations I've found in match bullets. I thought you guys might find it helpful.

Check it out at: http://precisionrifleblog.com/2013/01/29/berger-bullets-bearing-surface-variation/

 

[Gene]

I like the Davidson nose pieces sold by Sinclair. Install two of same caliber on your caliper, and they are very accurate. I sort into groups of .003" variation. But I shoot only Bergers in 6mm and 30 cal in competition to 500 meters, and have found little difference by sorting.

 

[Boss Hoss]

I'm curious... why do you believe the caliper method is so much less accurate? Is this based off of re-sorting bullets originally sorted by the caliper, using the Buhay tool? Do you have any guesses why a set of dial calipers that read to 0.001" would be less accurate than a dial indicator that reads to 0.001"?

I'm curious mainly because I have the twin stoney point set up - actually, one side is a Sinclair insert, way nicer, tapered hole, no 'rocking' like w/ the Stoney Point/Hornady inserts with their radiused hole) and have been considering the Buhay tool.

When y'all say the caliper method is faster... how much faster (best guess)?

TIA,

Monte

Monte best is correct in that the Buhay Tool is the gold standard it you will. Have been using it for many years and it does make a difference in my rifles. Do not know if it will make a difference in a factory rifle as I have not ever tried it. The bearing surface controls pressure which controls velocity variations and at long range the vertical dispersion is a bad thing...