with factory 150 corelok my best 3 shot group was 3/4. loaded up some loads with blc2,cci200lr primers,150 remington coreloks, 51.0 first 2 i heard the firing pin hit then it fired,1 time with 52.0. first 3 with 53.0 1.285. after that not good at all.do i need magnum primers?