Bullet sorting weight vs bearing length

[dmoran]

Variation in ogive, can be double/triple jeopardy compared to bullet weight, since it directly can effect bullet OAL, seating locations to the lands and/or seating location in the case. Hence, why it could be "more evil". Myself have seen little bullet weight effects on the targets, unless the weight indifference is more then a few tenths.

 

[Straightshooter1]

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.

Since I've done this test, I now measure a couple dozen for their bearing surface and BTO out of a batch to see if there's much variance. If there is, then I'll sort them all. But typically, I don't get much variance (like .002 - .004). For the BTO, if it's more than .003, I'll sort on that as I find it helps in getting consistent seating depth.

 

[carlsbad]

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.

Devin,
I'm sorting 184s today. I sort them by bearing length and I sort in groups of .001". Anything most are within .002 but several are well outside of that. Fliers?

--Jerry

 

[DHuffman]

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?

I always wondered how an accurate measurement was made because the boat tail has a sharper angle than the ogive so with two same size comparator inserts you are not even measuring the actual bearing surface and you are not accurately measuring the same distance from the bearing surface to each comparator either.

I'd like to know how to accurately measure this.

 

[DHuffman]

View attachment 1148049
Two Hornady comparators one on the bottom one on the top of the bullet in my calipers

In this picture it looks like you are using a Hornady insert on one end and a Sinclair insert on the other. Two sinclair inserts (bigger holes) would put you closer to the actual bearing surface and be a more accurate comparison of bearing surface in my opinion.

 

[jvw2008]

I looked at bearing surface in 180 Berger hybrids several years ago using Hornady inserts and then Sinclair inserts. The numbers were different but the bullets still ended up in the same piles. This suggested to me that the boat tail dimensions were not that important, so today I’ve settled on BBTO for sorting. I used to assess weight but have let that slide with any of my custom bullets. Weight wise they are amazingly consistent.

 

[Don Shelton]

Sorteez with a Sinclair comparator is my method,,,can sort as many bins as you want,,.001” is my standard

 

[T-shooter]

I think the method with the 2 Hornady comparators is good enough. It's probably very close and splitting hairs will probably not help the ballistics anyway. If the bullets are from the same lot the angles are probably close. This shows .223 bullets from the same lot measured one end at a time. This would seem indicate a .010" difference in the bearing surface as far as it can be measured by this method. This .223 insert and my .308 as both .010" smaller than the maximum diameter of the bullets.

I always seat from the front measurement and in this case, one bullet would set .013" deeper into the case reducing it's internal volume slightly. Unless the cases were cc'd, it wouldn't make a difference anyway. I wish I has weighed the bullets when I measured them.

 

[dbduff]

I have found the Sinclair mechanical gauge to measure base to olgive will lose accuracy over time,I think because of its repetitive use. I'm finding the electronic digital tool equally frustrating in that repetitive measurements, based on desired bullet sample, will migrate over time. If you return to the original projectile after 15-20 measurements, the original you based your sample on will often not measure what it originally did. I find my self after initial use questioning the tool's accuracy. It also measures out to 4 places past decimal point so maybe I'm overly thinking this. Sinclair advises to sort into groups no more than .005 in variance. Any thoughts on this, or am I going down a rabbit hole?

 

[LC Tikka]

For those who sort bullets to this level which is more important, weight or bullet shape.
Sorting by weight is easy but where in the bullet is the variations.
Bullet shape differences likely affects performance to be of concern.
Regarding bearing/shank length measuring, a vee-block tool with a dial gauge at 90deg to the axis to follow the profile and the other on the bullet base could determine the actual shank length as the bullet is moved along the vee-block.
LC

 

[Straightshooter1]

For those who sort bullets to this level which is more important, weight or bullet shape.
Sorting by weight is easy but where in the bullet is the variations.
Bullet shape differences likely affects performance to be of concern.

If by "bullet shape" you're referring something like just where the bearing surface begins and/or where it ends, then I'd say "bullet shape" is more important than weight for sorting. Most important to me (and not finding any significant differences in weight when I've weighed bullets), with regards to this, is to get a consistent seating depth so that my interior volume of the cartridge is consistent.

 

[Jet]

A few of you have asked what tool I use to measure bearing surface. The one Mark King use to make. Don't believe he makes them anymore.

Prior to using Mark King's comparator I tried using the Hornady tool with 2 6mm inserts. Couldn't get repeatable results when I did this.

To the OP. There are many methods shooters use to sort bullets and even more opinions on which measurements matter the most. Bearing surface, seating stem to ogive, base to ogive, overall length, weight, Juenke, Bullet Genie, diameter at the pressure ring, etc are things shooters do to keep variables down to a minimum.

Best advice as stated above--buy quality bullets. If you feel the desire to sort, pick a couple measurements and create sub lots. Recommend overall length first then base to ogive. Once those are done, see if it improves your groups at distance.

Good Shooting

Rich

 

[Hrsmn51]

Thanks guys for all the responses.
I had an idea this would open a can of worms.

This started on a typical blustery afternoon here in paradise, 20 mph+ to 60 mph gusts. Started weighing different manufacturers bullets and the difference was amazing. I weighed 100, 105 6mm and found 15 that were 105.0 to 105.05 the other 85 were 105.12 to 105.2, with one at 104.5 and one 106.7. I don't know if this is enough at 600 to take me off a 6 in target but this bullet historically produced fliers.
My goal was to try and eliminate some of the fliers that I couldn't call
Premium bullets = great advice

I would still like to hear more about measuring bullet consistency and measurable results I will post mine when the weather breaks.
GOOD SHOOTING and Happy New Year
H

 

[JMayo]

The 90 grain bergers I have, 3 different lots change in size/shape per lot. I don't weigh nor measure them.

The same lot of 105 don't change much & the same lot of 108's don't either.
I do weigh and measure them.

 

[newbieshooter]

I have found the Sinclair mechanical gauge to measure base to olgive will lose accuracy over time,I think because of its repetitive use. I'm finding the electronic digital tool equally frustrating in that repetitive measurements, based on desired bullet sample, will migrate over time. If you return to the original projectile after 15-20 measurements, the original you based your sample on will often not measure what it originally did. I find my self after initial use questioning the tool's accuracy. It also measures out to 4 places past decimal point so maybe I'm overly thinking this. Sinclair advises to sort into groups no more than .005 in variance. Any thoughts on this, or am I going down a rabbit hole?

Here's a good reference:
https://blog.ammolytics.com/2019-02-02/bullet-sorting-part-one.html

 

[Dusty Stevens]

Trust your bulletmaker. If you have to buy 2000 to get 1000 of what you think are good ones, think about the other stuff you cant see. How much is your time worth?

 

[dbduff]

Here's a good reference:
https://blog.ammolytics.com/2019-02-02/bullet-sorting-part-one.html

Thanks for this. I'm needing to do more sorting with the digital tool before I feel confident in the results. When my mechanical gauge was working I found the sorting to build both confidence and better scores. I'm convinced at this point that base to olgive variation affects point of impact. I'm a believer in sorting at this point.
D