Originally Posted by gspman
I am a little miffed at my measured velocity differences during my load development phase.
I have sorted all my cases (R-P brass),I have 24 3x reloaded brass. All weight within a half gn of each other.
I have sorted my accubonds so they are all the same weight exactly.
Tumbled, then ultrasonic cleaned prior to loading.
All brass sized to exactly the same dimensions. with the exception a some slight variance in case neck length.+/- .001.
This batch of cases was annealed prior to this loading.
I have each charge measured exactly.
Used rcbs charge master for all weight measurements and powder throwing.
Primer pockets all uniformed.
I got my best group with 74gn H4831sc measure at 2960, 3011, 2932.
3 in the x, perfect clover leaf (.4x in.)
How can i get this group with the variation in measured velocity, what can i change in my procedure to tighten this up some. bullet seated .010 off the lands.
I am scratching my head here?
Taking a reading of only 3 shots is a waste of time, it tells you nothing.
If you take an average of 10 shots, then get your ES, SD and Average velocity, you will have a far better idea of what's going on with your load. Once you know these factors, you can play with seating depth to 'fine tune' your load, or dabble with .3gr above and below your best powder charge to find the accuracy node. 74gr's of H4831 sounds a little soft to me, if you are using 180gr pills. You should be able to get 3100fps with a 180gr pill.
What was the max load grouping like?
Have you tried RE22 or RE25?
I look for a low SD in my loads, but as many shooters are aware, a low SD does not always give the best accuracy.
I too shoot a 300WM, and I look for a load that is near or at max, it gives me the best accuracy and I like to have a heavily compressed load with at least 100% fill capacity.
I really like RE25 with either 180gr AB's or 200gr AB's. Remington brass is fine if you take the time to prep it well.