30-foot tube of the 175mm gun points the direction. Its 150 pound projectile will travel up to 20 miles Marine 1stMarDiv 1969 Vietnam
Note the flak vests and M1 helmets without blouses, and the on-gun rack for the M16A1s. Source: 1stMarDiv [1st Marine Division] Photog: LCpl A. C. Prentiss Defense Dept. Photo (Marine Corps)