The howitzer has just been fired and the barrel is partially recoiled. Several members of the gun crew have their hands over their ears to minimize the effects of the massive concussion produced when shooting. Likely their earplugs had been lost but most men would not wear them in the heat and humidity anyway. Wearing them made your ears sweat and trapped the water inside.
The low angle at which this gun is being fired indicates that the target of its round is less than 2 miles from the fire base. They are shooting a small number of powder bags so the round emerges at low velocity and I was attempting to photograph the round emerging from the tube. Many of us tried to get a picture of the projectile but it required perfect timing and a fast shutter. Few succeeded.