LR benchrest primers vs LR mag primers?

[Bouieboy]

What advantages/disadvantages will large rifle benchrest primers and large rifle magnum primers have for 300 WSM and 270 WSM?

I have both, but have only use the magnum primers in these rifles.

Also, I'm shooting a custom 7mm-08. I've started loading it with the BR 2.

Thanks,
Bouieboy