I've used a lot of 7828ssc as well as the old standard cut in both the 270 & 280, & always with standard primers, mostly Federal 210M or occasionally CCI BR's.
Never a problem down to about zero, but never did an A/B comparison with a 215M mag primer primer either.
7828 is slow enough that it would likely work just fine with the mag primer, but the 270 case just does not hold enough powder to make me see it making much difference.
A trial or 2 would better answer your questions..........sometimes a mag primer actually gives poorer performance than a standard primer does.
YMMV
MM
