Bullet sorting weight vs bearing length

[Hrsmn51]

For best results what have you found to produce the best results. I weight sorted some 6mm bullets this evening and found interesting deviations from different manufactures.

This for a 6BRA and a 223AI

I am considering purchasing necessary equipment to sort by bearing length.
H

 

[rsmithsr50]

a lot depends on the initial quality of the bullet.
some benefit from bearing sort, some require both

 

[Straightshooter1]

For best results what have you found to produce the best results. I weight sorted some 6mm bullets this evening and found interesting deviations from different manufactures.

This for a 6BRA and a 223AI

I am considering purchasing necessary equipment to sort by bearing length.
H

Around Feb of last year I ran an experiment with my .308 with regards to how much difference I might see when sorting by bearing surface length. So I sorted some 168 SMK's and had two bunches at .033 difference. Because of that difference, I had to adjust and make sure the seating depth was the same as the longer ones tended to seat deeper and I didn't want to change the volume inside the case. I fired 10 shot groups alternating each 10 from the shorter to the longer. The last group wasn't very good, as I think I was loosing focus.

As it turned out, I did have a significant difference that you can see by the pics below. My conclusion is that unless there's a large difference like this, I'm not going to see much, if any, benefit in sorting by bearing surface length. And BTW, this was just before I started to anneal the brass, which accounts, in large part, for the rather high ES's and somewhat high SD's. But, even so, I think the numbers still speak for themselves.

The difference is bullet weights were so small I'm confident there was no measurable difference in the results, especially when you consider variations in seating depth effects results more than the variances in bullet weight. Not too, I also measured bullet length (see bullet weight pics), but ignored it for this experiment.

 

[David Christian]

Buy quality bullets and remove sorting from your process.

 

[Jet]

Straightshooter1

Thanks for sharing your test results. Based on your results, did the shot group of one bearing surface end up a little lower/higher than the other? Appears to in the photos.

A few years ago I tested some bullets (same lot) at 1000yds that had a variance of .014" in bearing surface. Point of impact between the two groups were about 12" apart in elevation.

Good Shooting

Rich

 

[338 dude]

For best results what have you found to produce the best results. I weight sorted some 6mm bullets this evening and found interesting deviations from different manufactures.

This for a 6BRA and a 223AI

I am considering purchasing necessary equipment to sort by bearing length.
H

I used to sort by weight but since checking the bearing surface length i use that, first off variances and bearing surface length will affect friction And velocity if it has a longer bearing surface it also is heavier so you are sorting by weight as well

 

[dmoran]

For those of you who are measuring the length of the bearing surface/bullet shank, how are you doing so accurately?
And with what tools and/or measuring devices are you using for the task?

 

[338 dude]

For those of you who are measuring the length of the bearing surface/bullet shank, how are you doing so accurately?
With what tools and measuring devices?

Two Hornady comparators one on the bottom one on the top of the bullet in my calipers

 

[dmoran]

Two Hornady comparators one on the bottom one on the top of the bullet in my calipers

Are your Hornady comparators hole sizes at bullet shank diameter, or are they not smaller?
If smaller, how do you get an accurate bearing surface length from between 2 compactors with smaller holes then the actual bullet shank diameters?

 

[338 dude]

Are your Hornady comparators hole sizes at bullet shank diameter, or are they not smaller?
If smaller, how do you get an accurate bearing surface length from between 2 compactors with smaller holes then the actual bullet shank diameters?

They are comparators whether or not the number is actually precise is irrelevant you’re comparing that bullet length to all the other bullet Lengths in your lot and separating them accordingly

 

[Mulligan]

Straightshooter1

Thanks for sharing your test results. Based on your results, did the shot group of one bearing surface end up a little lower/higher than the other? Appears to in the photos.

A few years ago I tested some bullets (same lot) at 1000yds that had a variance of .014" in bearing surface. Point of impact between the two groups were about 12" apart in elevation.

Good Shooting

Rich

Rich,
What method and tools did you use? Recommendations?
CW

 

[dmoran]

They are comparators whether or not the number is actually precise is irrelevant you’re comparing that bullet length to all the other bullet Lengths in your lot and separating them accordingly

I agree that is what your outcome is.... but has no relevance to the actual length of the bearing surface, is my point.
Just that the length of the bearing surface falls in between your length measurement from a point on the BT to a point on the Ogive, and does not tell you if the actual bearing surface has variation in length, or if the variations come before and/or after the bearing surface itself.

 

[338 dude]

I agree that is what your outcome is.... but has no relevance to the actual length of the bearing surface, is my point.
Just that the length of the bearing surface falls in between your length measurement from a point on the BT to a point on the Ogive, and does not tell you if the actual bearing surface has variation in length, or if the variations come before and/or after the bearing surface itself.

What is your method?

 

[dmoran]

What is your method?

For the must part, I have no method to measure the actual bearing surface lengths.
However, I can estimate the length with a micro-scope or optical comparator.

 

[338 dude]

For the must part, I have no method to measure the actual bearing surface lengths.
However, I can estimate the length with a micro-scope or optical comparator.

Estimate or compare I don’t see the difference

 

[JMayo]

#23 hornady comparators one on the bottom one on the top of the bullet in my calipers.

I'm not looking to actually measure, I'm comparing so to group. Wanting to get the ones on the end out of the match grade.
I usually have 6 or 8 rows out of 100.

 

[dmoran]

#23 hornady comparators one on the bottom one on the top of the bullet in my calipers.

I'm not looking to actually measure, I'm comparing so to group. Wanting to get the ones on the end out of the match grade.
I usually have 6 or 8 rows out of 100.

Me neither....
But I also know that any variations in length, may very well not be the actual bearing surface itself, and probable of being variation in ogive diameters at given lengths instead, thus failing to see why it is assumed/represented to be bearing length, or even named as so.

 

[Straightshooter1]

Straightshooter1

Thanks for sharing your test results. Based on your results, did the shot group of one bearing surface end up a little lower/higher than the other? Appears to in the photos.

A few years ago I tested some bullets (same lot) at 1000yds that had a variance of .014" in bearing surface. Point of impact between the two groups were about 12" apart in elevation.

Good Shooting

Rich

Yes. The significant difference was the POI, which I was interested in and not so much the size of the group. So, apparently you saw the same result even at .014 in, but at 1000 yds. Two different people, two different tests, two different times with same kind of results says something.

Like David Christian says . . . buy quality bullets.

 

[Straightshooter1]

I used to sort by weight but since checking the bearing surface length i use that, first off variances and bearing surface length will affect friction And velocity if it has a longer bearing surface it also is heavier so you are sorting by weight as well

I thought there'd be that weight issue too, but found no correlation. Note that I weighed each bullet in my test.

 

[Devin Wiggett]

I agree with David Christian. I just sorted 1000 Berger 184s by bearing length and the variance was only .002, hardly worth the effort. Spend more time shooting and reading the wind, and trust me David knows what he is talking about.