High Powered Airsoft (HPA) is the official recommended BB brand for Umbrella Armory. These BBs undergo the most rigorous QC measures to ensure absolute precision that is unseen elsewhere in the industry. Choose the right weight for you based on your fields rules, or your rifles FPS and barrel set up. All rifles using our Umbrella Armory R-Hop precision barrels should use .28g or heavier BBs to unlock the most potential from our upgrade. For higher powered Airsoft rifles, we recommend equipping .36g or heavier BBs to ensure the most precise and consistent flight path.