Re: Could Mag primers bring down my ES?
I agree that, before you start changing things in a good load formula, stretch out the distance and see how the groups hold up. I experienced some disturbing ES data with a chrono I had a year or more back that, until I figured out that was my problem, caused me to look at things that weren't actually wrong.
If you must mess with the load, start with neck tension. Turn necks, measure their thickness, select only matching cases (neck thickness, trim length, weight, capacity) in the set before you load. Use a certified accurate neck sizing die, measure each bullet and match them up in sets, apply consistent seating pressure and check for perfectly matching CBTO data before you change anything else. Of course, use a high quality chrono that is properly set up.
I have a great woman, fantastic kids, a warm place to sleep and an accurate rifle. Life is good ..............
Hunter Safety Instructor - Rifle/Pistol Marksmanship Instructor - NRA Life Member
American rifleman's triad - God, guts and guns. It built America and it'll preserve America. Abandon one and you lose them all.