Sorting cases by weight ??

[borderghost]

What is the general consensus on sorting cases by weight , is it best to do when they are new , or after prepping , neck turned , trimmed to OAL , ETC or will both ways work . Do you do the primer pocket / flash hole after a couple of firings.
Any opinions excepted.
Thanks

 

[dannyjbiggs]

What is the general consensus on sorting cases by weight , is it best to do when they are new , or after prepping , neck turned , trimmed to OAL , ETC or will both ways work . Do you do the primer pocket / flash hole after a couple of firings.
Any opinions excepted.
Thanks

The hypothesis for weigh sorting is that "equal weights of brass cases equate to equal case volumes" as a short cut to tediously sorting cases by "water weight"...ugh!! So, the more that you can streamline the weight of your cases, i.e. by all the case prep items you mentioned above to remove excess brass PRIOR TO FIRING, and of course before weight sorting the cases, the more realistic will be your ratio of case weight to volume. Not a correct science, but you know the alternative?!

Dan

 

[dmoran]

Myself, I do no qualifications until they've at least been fire-formed (at least 2-firings on wildcats). It is my experience volumes change during the initial firings, from the brass being stretched and ironed. When I do qualify them I do it by volume, and typically find pour correlation from case weight to volumes with most all cartridges, calibers, and brands of brass and Lots.
Donovan

 

[Twoboxer]

IMO it's a waste of time. Check a few from different headstamps (and years) and you can make your own decision. I never found a true correlation between case weight and case volume.

Whether it's different alloys or different weights at the base . . . dunno. For precision, I use new and keep batches together. For plinking, shooting like headstamps together (using the same load across all) was the simplest way to get them to shoot as alike as possible with the least work invested. If you have enough with the same headstamp (and year), it might be worthwhile to develop a load for that batch of brass.

 

[jcampbellsmith]

It depends a lot on the brass. I shoot 260 Rem. In the early days I used Remington brass and the cases varied by ~ 5gr. I used to sort the brass into approximately 1gr lots. Now I use Nosler and Lapua brass and don't bother weighing the brass.

Regards

JCS

 

[Sheldon N]

From what I've seen, there is a loose correlation between weight and volume but not much in the way of any correlation between case weight and velocity or case volume and velocity. No matter how you sort your brass you're not likely to improve ES or SD in any measurable way.

I personally fall in the "don't bother with it at all" camp.

The way to know that your sorting procedure is actually making a difference is this.

1. Weigh a large sample of unsorted cases with your preferred method.
2. Shoot all the cases, and record the velocity of each individual case.
3. Review the data...

If you had culled the heavy or the light ones, would it have improved your SD or ES? If you had sorted your brass into a "heavy" lot and a "light" lot, would it have improved your SD or ES?

If so, you can always sort them after the fact. If not, then you've learned something valuable and probably saved time in the long run.

 

[tenring]

IMO, sorting Lapua brass is a total waste. They are very consistent.

From what I've seen, there is a loose correlation between weight and volume but not much in the way of any correlation between case weight and velocity or case volume and velocity. No matter how you sort your brass you're not likely to improve ES or SD in any measurable way.

I personally fall in the "don't bother with it at all" camp.

The way to know that your sorting procedure is actually making a difference is this.

1. Weigh a large sample of unsorted cases with your preferred method.
2. Shoot all the cases, and record the velocity of each individual case.
3. Review the data...

If you had culled the heavy or the light ones, would it have improved your SD or ES? If you had sorted your brass into a "heavy" lot and a "light" lot, would it have improved your SD or ES?

If so, you can always sort them after the fact. If not, then you've learned something valuable and probably saved time in the long run.

 

[Das Capitolin]

What is the general consensus on sorting cases by weight , is it best to do when they are new , or after prepping , neck turned , trimmed to OAL , ETC or will both ways work . Do you do the primer pocket / flash hole after a couple of firings.
Any opinions excepted.
Thanks

Sorting empty cases by their weight isn't terribly beneficial, although some on the Internet would have you believe otherwise. Instead, if you're going to put much time into it at all, you'd be better off sorting by the prepped case's volume (water weight). At least then you'd be doing something to reduce ES and SD.

 

[Sheldon N]

you'd be better off sorting by the prepped case's volume (water weight). At least then you'd be doing something to reduce ES and SD.

Have you confirmed that you actually get a benefit from doing that? Ie. test all cases then compare the ES/SD of sorted vs unsorted lots?

In what I've seen from tests volume and velocity measurement and subsequent sorting has shown no improvement at all.

 

[Das Capitolin]

Have you confirmed that you actually get a benefit from doing that? Ie. test all cases then compare the ES/SD of sorted vs unsorted lots?

In what I've seen from tests volume and velocity measurement and subsequent sorting has shown no improvement at all.

For my 1000+ yard shooting, yes, there's improvement in vertical spread. For short-range shooting and chronograph data, there's not a lot to be gained but it is there.

 

[Sheldon N]

For my 1000+ yard shooting, yes, there's improvement in vertical spread. For short-range shooting and chronograph data, there's not a lot to be gained but it is there.

Did you actually shoot all the brass and note vertical POI for every case, then go back and compare volume and vertical POI to see if there was a correlation and whether sorted vs unsorted produced better results?

If you simply sorted the brass by volume (discarding some cases), did all your other brass prep and loading steps, and then went out and shot good vertical you have no way of knowing what factors were the cause of that. It would be like doing a scientific test without a control.

 

[Das Capitolin]

Did you actually shoot all the brass and note vertical POI for every case, then go back and compare volume and vertical POI to see if there was a correlation and whether sorted vs unsorted produced better results?

If you simply sorted the brass by volume (discarding some cases), did all your other brass prep and loading steps, and then went out and shot good vertical you have no way of knowing what factors were the cause of that. It would be like doing a scientific test without a control.

I'll let you re-read my suggestion, since you seem to be adding some of your own bias to it. Additionally, nobody is forcing, or even suggesting that you do any of this. YMMV.

 

[Hengehold]

From what I've seen, there is a loose correlation between weight and volume but not much in the way of any correlation between case weight and velocity or case volume and velocity. No matter how you sort your brass you're not likely to improve ES or SD in any measurable way.

I personally fall in the "don't bother with it at all" camp.

The way to know that your sorting procedure is actually making a difference is this.

1. Weigh a large sample of unsorted cases with your preferred method.
2. Shoot all the cases, and record the velocity of each individual case.
3. Review the data...

If you had culled the heavy or the light ones, would it have improved your SD or ES? If you had sorted your brass into a "heavy" lot and a "light" lot, would it have improved your SD or ES?

If so, you can always sort them after the fact. If not, then you've learned something valuable and probably saved time in the long run.

I am a LR sling shooter and have decided that weight sorting is not relevant for my application by conducting the following test at 600yds with Lapua brass.

1. Weight sort approx 100+ cases.

2. Shoot a 5 shot group with the extreme low weight cases.

3. Shoot a 5 shot group with the extreme high weight cases.

4. Observed that point of impact did not change between the groups of the two extremes.

Conclusion: if POI did not change then the extreme variables will shoot in the same group and not result in a vertical dispersion. This test could be replicated with a chronograph to confirm no change in velocity has occurred.

Bullet sorting: I conducted an identical experiment at 1000yds using bullet weight (sorted approx 500 Sierra bullets in .2gr increments) as the independent variable and testing the extremes. I did not notice a point of impact change in this experiment either.

Repeating these experiments with chronograph data would also be valuable but at the time I did not have a chrono available.

-Trevor

 

[Sheldon N]

I suppose I should let it go and let each shooter make their own decision. I'm comfortable with my choices and was primarily responding to the OP's question.

There's a lot of commonly accepted wisdom where people say "I do this and it makes a difference", but when you look into the underlying merit of those claims it's often assumption, placebo, correlation rather than causation, etc. Nothing wrong with that... it's their time and effort.... and it's true that confidence in your process gives confidence in your shooting.

My skepticism comes from the hard data of trying to test and show the correlation of weight sorting/volume sorting and velocity. When you go out looking for something in a concrete and measurable way and it's not there, it makes me curious how others have been able to find it.

As you said, YMMV.

 

[Hengehold]

Have you confirmed that you actually get a benefit from doing that? Ie. test all cases then compare the ES/SD of sorted vs unsorted lots?

In what I've seen from tests volume and velocity measurement and subsequent sorting has shown no improvement at all.

Value comes from testing and comparing the extreme differences. E.g. Largest capacity and smallest capacity. IMHO.

-T

 

[JimPag]

What is the general consensus on sorting cases by weight , is it best to do when they are new , or after prepping , neck turned , trimmed to OAL , ETC or will both ways work . Do you do the primer pocket / flash hole after a couple of firings.
Any opinions excepted.
Thanks

I have a Sartorius GD503 scale that weights down to .0001. Shoot SR score. After doing extensive tests over my Oehler 35P with weighting them and seeing the proof on paper and on the target, I came to a conclusion. Total waste of time IMO.

 

[Sheldon N]

Value comes from testing and comparing the extreme differences. E.g. Largest capacity and smallest capacity. IMHO.

Agreed. No matter how I sliced the data, whether culling the low or the high, or dividing into high/low lots, or looking just at the extreme low and extreme high, or even plotting a scatter graph showing all cases volume vs velocity and looking for a trend line... it simply wasn't there.

 

[ireload2]

The laws of physics says it is there. The trouble is it is masked by variations in neck temper, primers and the variations in surface area in each charge of powder. We might find the variation if we had a mile long bomber plant building to shoot in.

 

[Sheldon N]

The trouble is it is masked by variations in neck temper, primers and the variations in surface area in each charge of powder.

Yep, at the heart of the issue is the problem of stacked variability. If you have a variable (case volume) that in isolation could cause a deviation of 3-4 fps, and you add that variability to a broader data set that already has 8-9 fps of deviation from all other factors (primer, powder, bullet, neck tension, etc), you don't get a resulting SD of 11-13 fps. You only see an increase in SD of maybe 0.5 fps. That's just the fundamental math behind stacked variables.

You'd need a very large data set and very methodical procedures to demonstrate that 0.5fps SD improvement, and in the real world that just isn't readily observable or measurable.

 

[dannyjbiggs]

Sorting empty cases by their weight isn't terribly beneficial, although some on the Internet would have you believe otherwise. Instead, if you're going to put much time into it at all, you'd be better off sorting by the prepped case's volume (water weight). At least then you'd be doing something to reduce ES and SD.

I'm thinking that it would be a more accurate operation to standardize outside case size by "fire forming" the "prepped cases" and trim them to common OAL first, before undertaking the water weight tedium?

Dan