1. Equip either Armamentarium or Stoicism with spirit of Armamentarium and load into an activity or patrol etc. 2. Once in an activity you should see two grenade charges. When you activate unbreakable you'll notice your reserve charge gets deleted, not used, but deleted outright. The shield seems to behaves the same with or without Armamentarium though I haven't tested damage. You'd think you would be able to use Unbreakable twice without needing to recharge your grenade for the second activation.