U.S. Marines fire an 81mm mortar round during a joint mortar range exercise with Royal Saudi Naval Forces Marines called Red Reef 15 in the U.S. 5th Fleet area of responsibility, Dec 13, 2014. U.S. Marines fire an 81mm mortar round during a joint mortar range exercise with Royal Saudi Naval Forces Marines called Red Reef 15 in the U.S. 5th Fleet area of responsibility, Dec 13, 2014. SHARE: Download: Full Size (0.5 MB) Tags: Photo Essays Credit: VIRIN: 014464-I-FTI10-740.jpg Photo Gallery