Need help analyzing data...

[David Christian]

Hi all,

Without giving away the components, I was hoping someone with some excel skills could help me analyze the raw data attached (raw excel file attached along with pic of data). I took a box of brass and a box of primers and weighed each on my Sartorius scale. I selected the 10 heaviest and 10 lightest of each and loaded them using my regular load development and fired them over my Magnetospeed.

5 heavy cases matched with 5 heavy primers
5 heavy cases matched with 5 light primers
5 light cases matched with 5 heavy primers
5 light cases matched with 5 light primers


I know this is a very small sample set, but is there anything to conclude from the data?

Best,

 

[Bc'z]

Just by a quick glance.
Lightest primer and case weights produced the best/ tightest velocity spread.
I would actually need to break them up into the 4 separate groups to take a better look.

 

[Straightshooter1]

Hi all,

Without giving away the components, I was hoping someone with some excel skills could help me analyze the raw data attached (raw excel file attached along with pic of data). I took a box of brass and a box of primers and weighed each on my Sartorius scale. I selected the 10 heaviest and 10 lightest of each and loaded them using my regular load development and fired them over my Magnetospeed.

5 heavy cases matched with 5 heavy primers
5 heavy cases matched with 5 light primers
5 light cases matched with 5 heavy primers
5 light cases matched with 5 light primers

View attachment 1146648
I know this is a very small sample set, but is there anything to conclude from the data?

Best,

As you say . . . it's a very small sample set. And with and velocity ES of 43 fps indicating more of a variance in powder load that makes it virtually impossible to draw any reliable conclusion from this data. Interesting to me though, is when sorting the data by velocity and looking the the color dispersion, seems there might be some correlation with primer primer weight (e.g. a lot of purple for the lower velocities). As with any science, repeat ability is the key . . . as in, if you run the same test again and get much the same results, then . . .???

 

[praveen]

So, I did some calculations based on the 4 categories of data. It might help you draw some conclusions of your own.

Some of my conclusions:

Heavy Case + Light Primers produced the best ES and SD numbers.
Heavy Cases (with both kind of primers) had the best ES and SD numbers.
Light cases (with both kind of primers) had the worst ES and SD numbers.

 

[STS]

It's impossible to tell anything without knowing how you charged the cases. Did you weigh every charge to the kernel of powder or dispense it from a powder measure? In addition, the only reliable way of inferring any conclusion is to do a statical analysis of the data at different confidence levels. Not picking on you, but the experiment needs some refinement. I think you may find out what you are trying to learn with a bit of additional work. I'd like to know what the outcome is also.

 

[Bindi2]

All that tells me is the powder charge is not quite right. The ES is still to high.

 

[David Christian]

It's impossible to tell anything without knowing how you charged the cases. Did you weigh every charge to the kernel of powder or dispense it from a powder measure? In addition, the only reliable way of inferring any conclusion is to do a statical analysis of the data at different confidence levels. Not picking on you, but the experiment needs some refinement. I think you may find out what you are trying to learn with a bit of additional work. I'd like to know what the outcome is also.

Thanks for the note. Yes, I am definitely looking to understand how to set up such a test/experiment so that I can build my own set of empirical data. I will definitely repeat this test to include refinement suggestions from this group on how to make it better.

Each powder charged was loaded on my Sartorious. 63.488 grains lightest, 63.514 the heaviest. I shot the same exact load and set of components (unsorted cases and primers) earlier in the week and my 20 shot string had an ES of 24. Not great, but not the extreme seen over this mini test. Something is going on with matching up the extremes of each component, I just don’t know how to set up the test.

In summary, I am all ears and looking for suggestions on how to conduct this type of test so that I can prove to myself case sorting and primer sorting.

thanks!

 

[1911nut]

I sure hope sorting primers by weight isn’t proven to shrink groups.

I don’t think I’m strong enough

 

[Webster]

Hi all,

Without giving away the components, I was hoping someone with some excel skills could help me analyze the raw data attached (raw excel file attached along with pic of data). I took a box of brass and a box of primers and weighed each on my Sartorius scale. I selected the 10 heaviest and 10 lightest of each and loaded them using my regular load development and fired them over my Magnetospeed.

5 heavy cases matched with 5 heavy primers
5 heavy cases matched with 5 light primers
5 light cases matched with 5 heavy primers
5 light cases matched with 5 light primers

View attachment 1146648
I know this is a very small sample set, but is there anything to conclude from the data?

Best,

What do the groups look like?

 

[riflewoman]

I would run two one way ANOVA tests comparing the heavy vs light primers independently, a one way ANOVA comparing light vs heavy CASES, then a two way ANOVA test comparing the combinations. HOWEVER, from what I see you don’t have nearly enough data. You need a sample of 20 each (maybe as few as 15) of each of the 4 combos.

https://www.statisticshowto.datasci...lity-and-statistics/hypothesis-testing/anova/

 

[Straightshooter1]

If I were running this test, I'd probably run it something like this:

1. Sort like 100 cases of the same brand, or more if needed, and select 20 that are virtually the same weight.

2. Sort primers and select 20 that are virtually the same light weight and 20 at the same heavy weight.

3. Sort bullets by weight and select 20 that are the same (including the BTO measurement).

3. Prime the 20 equal weight cases with the light weight primers.

4. Charge the cases making sure the powder measurements are all within one powder gradual in weight.

5. Seat bullets to same depth

After firing and recording the chrono data, under the same conditions, I'd do 3 thru 5 again using the 20 primers that were heavy using the same cases that are prepped in the same way and keeping them in the same order all the way through the firing sequence.

Then if to test effects of the variance of the case weights, I've do the same thing as above, only keeping the primer weight constant and using case weights at both ends of the spectrum.

I suspect a difference might be seen in the data, but just how significant is probably not going to be seen on paper at 100 yds, even at more distance unless the shooter is very, very good.

 

[mikecr]

Determine actual capacity of cases, group them matching, see ES drop.
The meaning of primer weight is even slipperier than the meaning of case weight..