The audio of this gripping video is very graphic ... and depicts men under fire at Operation Red Sand in Bala Murghab, Badghis Province, Afghanistan, April 4, 2011 ... including the actual moment an RPG lands among the American troops wounding Army Sgt. Jeff Sheppard, Pfc Ben Bradley, Air Force Master Sgt. Kevin Wallace, Navy Petty Officer 3rd Class Ryan Lee, and Navy K9 'Valdo'.

The wounded and their fellow troops reactions are heard, as well.