Lee Precision Quick Trim Die 6.5 Grendel

I have many of these and by far they are the simplest, quickest, and most uniform way to QUICKLY trim cases. There's a small learning curve to the system, but you'll quickly get the hang of it.

This works perfectly with the Lee Quick Trim System. Unlike some of the other quick trim dies, this has a gasket like material that grips the brass and keeps out the shavings. Best price I found was here.