Bolt lugs have bad peening with low round count - Aero Precision AR-15 6mm ARC, 6.5 Grendel Bolt Carrier Group (BCG)

The back of pretty much every lug is rolled up. Round count on my 6 ARC (18" stainless Proof Research barrel) is under 400 rounds. Rifle has an adjustable gas block and mostly suppressed, but still... Compared to a BCM 5.56 bolt on an 11.5" SBR with over 1000 rounds mostly suppressed without an adjustable gas block, the Aero is horrible. The BCM has almost no wear.

The actual carrier is okay. The firing pin retainer pin is difficult to get back in compared to every other carrier I've pulled apart. It's definitely on the just okay scale.