These guys are definitely steering you in the right direction. I have nothing “new” to add to what they have told you, just what I use. For my precision rifles I use either the Redding or forester micrometer seating dies, I use Redding bushing neck dies for casings that have turned necks, and either Redding or forester neck dies for ones that don’t have turned necks. I use Redding full length or body only die for when the shoulders need to be set (bumped) back. Some people bump the shoulder every time. For precision, you will want to only use brass for one rifle, so keep your brass separate per rifle. For your AR you will more than likely need to full length size every time, you will just need to experiment to see.


JTD