Partitions also shoot to much different points of impact than ballistic tips or accubonds in my 300ultramags.Partitions also don't group well in my 7mmstw's or 300ultramags despite having tried several bullet weights and powders such as r-25,imr7828 and h-1000.You can try different powders but some guns just don't like some bullets.I actually get the best results in larger cases using federal 215 primers.