Reduce extreme spread 338 Edge

[montanarichard]

I am having trouble getting the extreme spread down on my 338 Edge.

28 inch barrel

300 SMK CCI 250, H 1000 @ 90.0 Gn. COAL 3.790

<.50 groups @ 100 Yds

all Remington cases total prepped and weighted, all bullets weighted.

Powder measured to .1 grain on both electronic scale and balance scale.

chrony beta set in box with over head lights at 10 feet.

typical string

2722, 2723, 2692, 2647, 2652, 2726, 2747, 2752, 2674

any ideas on what is causing the extreme spread?

 

[cmillard]

where is the bullets seated in relation to the lands? also, what primer?

 

[Dans40X]

Case neck prep/sizing
Primer selection
Powder selection other than Hodgdon!!

 

[Minesweeper3433]

2722, 2723, 2692, 2647, 2652, 2726, 2747, 2752, 2674

2722, 2723, 2726, 2747, 2752
2692, 2647, 2652, 2674

I would rerun the test to see what is giving you split sets?
It looks like you have something that is causing a yes or no type split in your casses.
I would do it again but ones in the faster group get separated from ones in the slower group and then try it again by only using one of the groups to see if it is something in the brass.
You could also split into smaller sets if you have the volume of brass needed to get a good batch.
2722, 2723, 2726
2747, 2752
2647, 2652
2692, 2674
That is what I would do anyway.