Firing Skills Marines fire high-caliber rounds from an anti-tank weapon to hone firing skills in Djibouti, April 19,2016. The Marines are assigned to the 13th Marine Expeditionary Unit, which is conducting sustainment training to maintain proficiency and combat readiness. Marine Corps photo by Cpl. Alvin Pujols SHARE: Download: Full Size (1.6 MB) Credit: Lance Cpl. Alvin Pujols VIRIN: 160418-M-NM524-005A.JPG Photo Gallery