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How to measure,base to ojive, and is BTO, more important than .1 of a grain for sorting bullets 108s

I picked up a Hollands last year to check base to ogive and retired
my old method. It's quick, easy and extremely efficient. I do not miss
using calipers at all. And as an added attraction using the 6mm die,
you can sort 22LR rim thickness. Know lets talk sorting primers and
why I became a convert.......
 
Please share your valued and underpriced “2 cents worth” on how you sort.
For match/comp ammo, by the fallowing ways, and in that order:
  1. BtO / Base to Ogive --- (by Dial-Indictor Stand)
  2. BtS / Base to Seater Stem --- (by Dial-Indictor Stand)
  3. OAL / Overall Length --- (by Dial-Indictor Stand)
  4. Diameter --- (by Micrometer Thickness Gage / 0.00005" resolution)
  5. Weight --- (by a 100th Scale)
------------------------------------------------------------------------------------
 
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I don't have anyone to teach me this stuff, except y'all Iv been to a few matches. Put together a dozen or more Br rigs. I read on here. It's certainly an addiction. I guess it's a good one though.
Sorting bullets!
I'm sorting Berger 108s. In this picture, Is this the correct way to measure base to ojive?
If it is ,will work this way? , Is this more important than say a .1 of a grain difference in bullet weight?
I started measuring some and right away I started seeing a variance.
I seat my bullets in a away I try and get the ojive of the bullet say .010 from lands. But Iv noticed when I set my die I still get a variation. I'm hoping this will go away if I sort.
I would not want to try and compare the value of sorting bullets BTO versus sorting bullets into 0.1 gr increments. For what it's worth, I don't do either of those things, and I susoect it's not an "apples-to-apples" comparison, anyhow. Regardless, others are welcome to test and attempt to define the relative value of those sorting approaches if they wish.

What I can tell you is that length-sorting Berger bullets can most certainly be of benefit, but I'm talking about sorting by overall length, not base-to-ogive. In my hands, the BTO measurements of the various Berger bullets I use are actually pretty consistent. In contrast, there is a fair bit of overall length variance in every Lot #/batch I've ever sorted. Typically, I observe an OAL variance of up to .015" to .020" in a Lot # of Berger bullets, usually with a very small number extreme outliers that would push the average length variance even higher if included.

What it means when the BTO measurements are fairly consistent, but the OAL measurements have significant variance is that the majority of length variance lies in the nose region of these bullets. This is important for your question because the two critical contact points for seating depth, i.e. the point where the seating die stem contacts and "pushes" the bullet down into the case, and the point on the bullet ogive just above the bearing surface where our caliper insert contacts the bullet when we measure caertirdge base-to-ogive (CBTO). Any length bullet-to-bullet length variance between these two critical contact point can therefore lead to seating depth inconsistency.

As illustrated in the cartoon below, both of these critical contact points lie outside the BTO dimension. In other words, sorting bullets by BTO is not going to improve seating depth variance caused by length variance in the nose region of the bullet. For that reason and for the purpose of pointing bullets, I sort them by OAL, not BTO, and the benefits of sorting by OAL and pointing can readily be documented on a target at distances of as little as 300 yd. The elevation required to center a group at 300 yd typically decreases by about 1/8th to 1/4 MOA for pointed bullets as compared to unsorted/unpointed. This is not surprising as it is well documented that pointing bullets increases BC by a small amount, so they require a bit less elevation at a given distance. However, in my hands the groups also routinely became tighter, which I suspect may be a function of the length-sorting process, at least in part. If you're wanting to see whether length-sorting can help with seating depth consistency, try sorting by OAL and see how it works for you.

Bullet Dimensions2.png
 
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To get a little anal about it; We have a contact point when checking
base to ogive and sort from that point. Now comes the seater point
of contact. That area may be all over the map and causing varying
seating depths. One would think that the seater should make exactly
the same contact point as does the base to ogive tool.....I modified a
seater plug to to be further down on the bullet and be closer to the
point of that contact. Every little bit can't hurt !!
 
Ned,
Seating depth variations aside, do u think that the differences in bullet nose length affects the bullets flight?
I soft seat my bullets long and let the gun find the seating depth. My bullets are sorted by bearing surface length. Bullet wt. I find is in direct relationship to bearing surface length.
So for me, there is no variation in seating depth. The only variable is the actual difference in the length of the bullet nose.
Thoughts?
Bob
 
I’ve been sorting from base of bullet to the tip keeping them in groups of .003 and I can get batches of 70 to 80 out of 500 enough for a F class match this way. It seems to help with my scores but I can’t say with certainty it does.
 
I’ll jump back in to this thread with a little tid bit for those guys sorting bullets several ways.
To avoid chasing my tail I’ll sort.
1- start with oal
2- base to seater stem diameter ( Wilson VLD stem approx .17 comparator insert)
3- base to ogive
4- weight ( optional)
For loading and once the seater die is set to my predetermined optimum depth I switch to the .17 insert to monitor the seating consistency and most results are within the limits of my calipers .0005
 
Ned,
Seating depth variations aside, do u think that the differences in bullet nose length affects the bullets flight?
I soft seat my bullets long and let the gun find the seating depth. My bullets are sorted by bearing surface length. Bullet wt. I find is in direct relationship to bearing surface length.
So for me, there is no variation in seating depth. The only variable is the actual difference in the length of the bullet nose.
Thoughts?
Bob
To be honest, I don't know with certainty, but it could. For that reason I sort bullets, and I don't mix different sorting groups in rounds loaded for a single match. I don't find sorting bullets to be all that tedious and thus worth the effort. I do also weigh bullets, but not to sort into groups of 0.1 gr increments. Rather, I am merely looking to cull any gross weight outliers. There always seem to be a few in every Lot #.

I make an effort to improve the consistency of the bullets I use from straight out of the box. However, I don't want to live in the reloading room, and I don't want to sort bullets to the point I end up with a single unique bullet in each of thousands of sorting groups. In general, I believe determining which sorting process works best is something that everyone needs to do for themselves. In other words, try a few different techniques/approaches and determine whether you can actually shoot the difference on the target. Then decide what best fits into your reloading process and provides the greatest return on the investment of time/effort.
 
To get a little anal about it; We have a contact point when checking
base to ogive and sort from that point. Now comes the seater point
of contact. That area may be all over the map and causing varying
seating depths. One would think that the seater should make exactly
the same contact point as does the base to ogive tool.....I modified a
seater plug to to be further down on the bullet and be closer to the
point of that contact. Every little bit can't hurt !!

Bingo. I did a bunch of measuring and found the same thing. I built a comparator out of a wilson seating stem (same type of stem I use in my seating die.)
 
Short range, base to o.
Long range, OAL.

My two cents.
Aaron,
Sorting by OAL for long range, what sort of SD do u see at say the 600 yd target? I ask cause although ur OAL is the same/ similar, the bearing surface is varied. To me, that is the area of the bullet directly in contact with the bore. variations in that contact patch can certainly affect ur velocity spread n that equates into vertical at longer distances.
I am not shooting off bags/ rests so maybe my mileage is different than urs.
Bob
 
Ned,
Seating depth variations aside, do u think that the differences in bullet nose length affects the bullets flight?
I soft seat my bullets long and let the gun find the seating depth. My bullets are sorted by bearing surface length. Bullet wt. I find is in direct relationship to bearing surface length.
So for me, there is no variation in seating depth. The only variable is the actual difference in the length of the bullet nose.
Thoughts?
Bob
I heard about this guy ,his last name was Whidden I think, he shot a .243 and it was a article l. believe I read . And that was how he seated his bullets.
I thought that's what the article meant by " soft seating".
 
I heard about this guy ,his last name was Whidden I think, he shot a .243 and it was a article l. believe I read . And that was how he seated his bullets.
I thought that's what the article meant by " soft seating".
Yes, I use John’s “ Soft Seating” method. U never chase the lands for the life of the bbl.
Have used his method for 308, 6mm BRX, 6XC, and 6.5x284. This is for MR n LR prone.
It works.
 
Yes, I use John’s “ Soft Seating” method. U never chase the lands for the life of the bbl.
Have used his method for 308, 6mm BRX, 6XC, and 6.5x284. This is for MR n LR prone.
It works.
Since you put that way, that makes sense.
So if I went back to using this method how much longer should I set bullet depth?
How much should each bullet be moving back into the case ? If the the Jam point is say 2.400 long
Should I try and load 2.405 or 2.410 or longer?
 

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