I feel this was the issue, I had never operated a chronograph, I was shooting 3 feet from it . Since then I have had good success with ramshot magnum, H4350, and most recently H1000. Thank you so much for your input, it confirms my situation.I shoot a Bergara MGLite .300 WM and load RS Magnum 83.5 with 200 gr ELDX rounds exclusively. I am getting 2935 FPS with an average 11fps variance. I had trouble with my chronograph also initially because there was a roof over our shooting table. I moved it out away from the structure, about 10 yrds, and it showed the more accurate speed first shot. Not sure it that is your issue, but solved my problem.