CCI Primer weights.

[Rocketvapor]

I agree. Someone needs to do more tests, Yay or Nay Data.

Data, Midrange or longer, not "I can't see nothin", Data.
Unsorted won't do it, no idea what you loaded and shot.
There's probably 970 GOOD primers per brick.
Load as many outlier weight primers as you can (might take 3 or 4 bricks to get 100).
Show targets, not 100yd groups, even I can get some good 100yd groups.
Use a Chrono.

I think some of the variables were taken out by shooting 30 rounds Round Robin, slow fire.
Same lot of cases weight sorted, same lot of Berger bullets , loaded as uniform as I could.
My data was from a 28" AR in 22 Nosler. 85.5 Bergers, SB6.5, velocities in the neighborhood of 3000fps.
I'm almost a MOA shooter @ 600.
If I can SEE primer weight on target, I bet a better shooter can see it also.

Load and shoot for a match with your BEST procedures and throw primer weight out with the wash?
Use whatever you do for a match, throw in a couple light and heavy primers into your match ammo. Report back

 

[RegionRat]

Not sure what happened when I translated/imported the data but it didn't get all the initial weight correct on all the points.

No worries. That happens to me too, when using OCR to lift screen data or scans and translate it into usable numbers.

 

[RegionRat]

How is heating and cooling, continual fouling of the bbl vs friction taken into account?
Bullet uniformity, weight and ogive sorted?

Part of the challenge in open forums, and in non peer reviewed work in general, is you never know if the author has everything else under control.

With some experience, you can start to tell when folks are drawing conclusions on noise and luck, or when they are doing a good job.

Winds are confounding, but a decent waterline at 600 yards or more is usually not due to random luck when there are enough shots, and on multiple outings.

Heating and fouling are part of the small arms landscape and are always present. That is not to say every gun and recipe will work, but the ones that do work are all carrying these issues too.

Shooting machine barrels get hot as they shoot, and someone has to clean them too. As consumers, you rarely if ever know how the labs are running these tests or if the technicians know how to clean a barrel when they publish loading manuals.

You are asking the right questions, and those answers are the ones that separate the beginners from the High Masters. Carry on.