In shotgun, no. In rifle, there is a difference. In my Pedersoli Mortimer "Whitworth" .451 not (hexagonal) I find that I get slightly better groups with regular than magnum caps. But, using the same caps all the time is more important. Group size also changes with load and fineness of powder. Virtually anyone shooting rifle competitively uses Swiss or Eynsford, probably 2FFg or 3 FFg. Right now, most folks are shooting whatever powder they can find, exclusively.
Best of luck with it.