I read on a forum awhile ago that some guys where using large rifle primers in there 300 win mag casings instead of magnum primers to get more a more consistent velocity. They reported having a a higher and more consistent velocity on average. Is this something that is safe to do? I'm assuming you would want to start at the start charge or maybe even below it to check for pressure signs. Has anyone had experience with this and if so, what are the pros and cons for using large rifle primers over magnum primers?