Howitzer Work Soldiers with the Illinois National Guard conduct maintenance on an M777 howitzer at Camp Grayling, Mich., July 21, 2019, during Northern Strike, a National Guard Bureau-sponsored exercise. SHARE: Download: Full Size (1.49 MB) Tags: Army Credit: Army Spc. Leona Hendrickson VIRIN: 190721-Z-OD934-094C.JPG Photo Gallery