Blackelk, you did not identify primers you are using. You might try different brands as changing primers can give you significant changes in your SD/ES readings.

I have conducted testing at 300 yards on chronograph using same cases, same propellant, same bullets, same rifle,same temperature and just changing primers brands and primer lots can give you big changes.

I ran Federal, Winchester, CCI and Wolfe. Lets say there were number 1, 2, 3 and 4 for test purposes.

With a given load lets say 1 was best, 2 was second best, 3 was third best and 4th was worst. I changed propellants and no 3 was best, no 1 was second best No 4 was third and so on. There was no rationale and no #1 primer across the board.

Now I have also run into similar with the same brand of primers and a different lot number.

How many rounds on your barrel? It may be time to touch up the crown on your barrel.
http://www.fulton-armory.com/%5Cfaqs...%5CTEGauge.htm