Primer Weight

[memilanuk]

Most cheap calculators will have an Average and Standard Deviation (sigma) on there and we have taught uneducated third world peasants to run QC samples.

It really isn't hard, our schools just suck.

Those peasants probably didn't brag about their ignorance of math more complicated than 2+2=4, either.

 

[Rocketvapor]

and now page 5
If you can find an outlier from 30 to 100 primers, you is either unlucky, or got a bad batch.
MAYBE one or two light and/or one of two heavy per 1000. Maybe in one brick, but not another.
Count your Sigmas. A true outlier will be 0.1% of product or less of a process in control.
For those shooting a group with light primers and another group with heavy primers and expecting to see a difference, good luck. Those where ALL good primers. I would also NOT expect to see any difference within the first few hundred yards.
Use grains, grins or grams. Just have the resolution to see "bins".
Here is one brick of CCI450 primers, sorted to about 0.02 grains. I would NOT expect to see ANY difference in performance with any close to the mean. I did not shoot the extremes. Maybe one day.

That's a range of 0.165 grains.
Can your shooting discipline live with a few odd shots per thousand?

 

[Dave M.]

For both Dave and Tom......You both are long range shooters, so let
me ask this......How large of a charge are you loading and it's burn
rate area ?? I mainly shoot short the last few years with cartridges
that load below 35 grains of powder, and powders that are faster
then Varget.....What I'm getting at is; A primer sort is more conclusive
with a much smaller BR cartridge then it would be with something
used in the LR game. Quite honestly, were talking a good average of
a 20 grain charge of more powder, of which it is a much slower powder.
I would offer my conclusion that there is a point that the value of the
sort would get meaningless as the charges increase with slower burning
powders......

I load three cartridges primarily and ALL using Lapua brass:
1. 6 dasher - 33.1-33.3gr of RL-15
2. 6.5CM - 42.0-43.0gr of H4350
3. .284 win - 50.3-51.0gr of H4350

 

[Dave M.]

and now page 5
If you can find an outlier from 30 to 100 primers, you is either unlucky, or got a bad batch.
MAYBE one or two light and/or one of two heavy per 1000. Maybe in one brick, but not another.
Count your Sigmas. A true outlier will be 0.1% of product or less of a process in control.
For those shooting a group with light primers and another group with heavy primers and expecting to see a difference, good luck. Those where ALL good primers. I would also NOT expect to see any difference within the first few hundred yards.
Use grains, grins or grams. Just have the resolution to see "bins".
Here is one brick of CCI450 primers, sorted to about 0.02 grains. I would NOT expect to see ANY difference in performance with any close to the mean. I did not shoot the extremes. Maybe one day.
View attachment 1513750
That's a range of 0.165 grains.
Can your shooting discipline live with a few odd shots per thousand?

Precisely my findings. It was just not possible to see any statistically significant conclusion that could be drawn.
Dave

 

[Rocketvapor]

Maybe when I do another brick or two the distribution will fill out (on the light end).