Barnes BRNS 6mm ARC 105 Grain Open Tip Match Boat Tail OTMBT Rifle Ammo 20 Rounds. BRNS 6mm ARC 105 Grain Open Tip Match Boat Tail OTMBT Rifle Ammunition Specifications for Barnes BRNS 6mm ARC 105 Grain Open Tip Match Boat Tail OTMBT Rifle Ammunition: Manufacturer: Barnes Caliber: 6mm ARC Number of Rounds: 20 Bullet Type: Open Tip Match Boat-Tail (OTM-BT) Bullet Weight: 105 grain BRNS 6mm ARC 105 Grain Open Tip Match Boat Tail OTMBT Rifle Ammunition