Get yourself a hand primer...if your not seating your primers deep enough it can cause miss fires and inconsistent ignition and to deep will cause inconsistent ignition...you want to feel the primer just bottom out then apply just a tiny bit of pressure to make sure the anvil is seated.

you have a great die for neck sizing but make sure your getting about .003-.004 neck tension.

you don't need the BRs but they are the most consistent primer I've used and the CCI200s are right there too...like I said I would shoot the exact same test with the CCI primers and see how it goes...if your ESs are still high I'd play with neck tension next.