6 Dasher is great, Alpha and Peterson brass make it the easy button. I'll always have an affinity for the 6BR though.
Seems like the PPCs have a different bolt face. They definately have a different case head, but I can't remember if they can be run in the standard 308 or not. Pretty much all bolts exist now anyways, but it's an added expense if you haven't previously run the PPC. I've been beat by them many times though.
I went Dasher because I had a 308 BF short action that was doing nothing that needed a barrel, and my benchrest action was a 6BR previously. Bought 2k pieces of brass and never looked back.
6BR, BRA, BRX, and Dasher are all the same case. I've never seen anyone have issues running any of them, PRS or benchrest. Shoulder angles, extraction, none of that matters other than putting a block in 308 AICS mages so that they feed correctly.
If you want to try to load it hot and squeeze out every FPS maybe, but normally I'm happy with a slower node. In the neighborhood of 2.8k with a 100+gn bullet does everything I want a 6mm to do. If I need 3200+ 243 AI exists.
Lower pressure loads will last forever, 30+ firings on bench rifles with a good sizing plan.