You can hear the “sound” just looking at some photos.
Caption: An artillery round exits the barrel of an M777A2 155mm Howitzer during a live fire exercise by 2d Battalion, 8th Field Artillery Regiment, 1st Stryker Brigade Combat Team, 25th Infantry Division at the National Training Center in Fort Irwin Calif., Feb. 19. Soldiers from the 2-8 FA are training at the NTC during a month-long rotation in preperation for the 1/25th’s deployment to Afghanistan later this year. (U.S. Army photo by Spc. Michael Blalack, 1/25 PAO.)