Long range primer comparisons

338LM

Sergeant
Full Member
Minuteman
Jun 20, 2003
502
55
STL Missouri
Has anyone done any primer comparison testing at 800-1000+ yards to see if your groups tighten or open up with various primers such as BR2's, 210M's, WLR's, etc.
I totally understand that this would be a difficult test with so many other variables factoring in at these distances.
I myself have worked my way up to 800 yards. I have not seen any difference in group sizes between the above mentioned primers. I am now wondering if primer selection will make a difference in groups above 800 yards?