Thanks for the comments. I have spent a lot of time on my reloading tech this last 2 weeks. I bought new Lapua case, sorted bullets by bearing wall lenght, since I did not have time to shoot the case and neck-size, I will shoot them as is (out of the box) So I sorted the case by weight, and I made lots of 18 bullets and case, all similar one from another. Bullets bearing wall lenghts varied from .442 up to .4495. I sorted them in 0.0005 increment, this gave me 16 bags. Then the one that had 18 or more of the same are being used for 600 yards, the others regrouped and used for the other distances.
Lapua cases varied from 94.4 grain to 96.3, all sorted with .1 grain difference. Then I regrouped to get 18 cases close to one another.
I also reload relay by relay. The next match has 300, 400, 500 and 600 the first day, and then 400, 600, team match at 600 and the final at 600. So I have 7 bags of 18, and one bag of 13 for the team match (2/10). I prepare 18 per relay, even if I need only 2 sighter and 15 for score, this way if something happens I will be ok.
While reloading, I found out that my bullet seater die (the Lee) sometime gives a bit of difference from one another (less than 0.001) usually. I do measure all the ammo with the Hornady comparator, and I also sort the 18 ammo per relay by final lenght in my box. This way, even if I have some small variance in lenght, I will alway ensure that one round to the next will be as close as I can make them.
Thinking about making a new stock for next season, we are working with maple right now at work and there will be left-overs.....