"There were thousands of fragging threats during the Vietnam War, most of which were never acted on. There are at least 800 confirmed attempts in the Army and Marines. 86 of the officers and sergeants were killed and approximately 700 were injured. This is only the documented cases. The true number of fraggings may never be known."
And this: "Several hundred murders of U.S. soldiers by firearms occurred in Vietnam but most were of enlisted men killing other enlisted men of nearly equal rank."