Apologies in advance: my eyes glazed over reading search returns.

Anyway, loading plinking ammo. Using up an assortment of OLD primers. Happy load with 55gr fmj, 24.2-24.7gr Shooters World AR Plus (I understand 26.2gr to be suggested max) cci 400 primers, lc brass. KIM, plinking ammo so would rather not waste components on further load workup (after these cci's loaded, will be down to 100 of these, 60 of those, etc.).
Question is: How worrisome are effects of going from "standard" small rifle primers to magnum primers (Win SR Magnum in this case? Was hoping to just load everything on out with 24.2 or so grains and blast away.

Thoughts?

Thanks