NAJAF, Iraq - The burst lasted just three seconds, but it was long enough to catch the ear of every U.S. soldier on this captured Iraqi army post, sending some scrambling for their rifles and others scrambling for cover.
It was also long enough to fire 24 bullets, their hot brass casings clattering to the bloodied tile floor.
A young lieutenant hopped out of the barracks room on one foot, shouting for a medic. He lay down, then directed the men who rushed to his aid to look inside.
A sergeant was down, blood filling his left boot. A specialist took a bullet in the thigh, precariously near his groin.
When the commotion cleared, a young private first class sat outside the doorway alone, hanging his head between his knees. He had joined a mortar platoon of the 2nd Battalion, 327th Infantry of the 101st Airborne Division only six weeks ago, a few days before the unit left Fort Campbell, Ky., for war with Iraq.
Before that, he was in basic training.
Accidental discharges, as the Army calls such shootings, are an inevitable part of war, when thousands of soldiers are carrying and cleaning loaded guns. It is precisely for this reason that most Army units weren't issued ammunition until after they had been in Kuwait for several weeks, right as the war started.
This battalion had its first accidental discharge last week, when a guard handed another guard a sniper rifle during their shift change. The safety was off, and one of them bumped the trigger. No one was injured.
"When you have 18-year-olds with guns and things that blow up, they are going to make mistakes," Lt. Col. Chris Hughes, commander of the 2nd Battalion, called No Slack, told his staff Sunday as he reiterated a battalion rule: No loaded machine guns indoors.
Since last week, No Slack has been conducting search and destroy operations around Najaf, a city about 80 miles south of Baghdad. This weekend it moved into a compound of low, concrete barracks in an abandoned Iraqi army post on the desert's edge, north of town.
The private was cleaning his M-249 machine gun after guard duty when the shooting occurred. The M-249 is called a SAW, for squad automatic weapon, and it is a serious machine gun. It weighs about 14 pounds and fires 5.56-millimeter bullets at up to 725 rounds per minute.
It is primarily used to lay down a field of fire, forcing enemy soldiers to hug the ground or die.
According to the incident report, the private was breaking down his gun to clean it and had removed the butt stock and the trigger mechanism. The trigger mechanism not only allows the gun to fire, but also stops the gun from firing when the soldier isn't pulling the trigger.
On Sunday morning, something was stuck, and the private was banging at the bolt. When it freed, the firing pin struck a bullet in the chamber. With no trigger mechanism to stop it, the ammunition belt just kept feeding into the gun, and lead kept coming out.
The private dropped the gun and briefly sought cover against the smooth concrete wall. The SAW chattered and danced around the floor clockwise, spraying bullets off the tile floor and the concrete walls as a half dozen soldiers vainly sought cover.
A Sony Walkman was blown to bits. There were rips - but not holes - in at least two protective vests. A ricochet smacked into a soldier's Bible, but the lead never got past Genesis.
The private dove onto his weapon, and the belt broke. The gun was quiet.
The lieutenant, the private's platoon leader, was shot once in the ankle. The bullet traveled up his calf and lodged behind his knee.
The specialist was hit in a hand, an elbow and his left upper thigh.
The sergeant was hit behind the left knee and in his left foot. The bullet bit off his third toe.
A Blackhawk medical evacuation helicopter landed in the dirt parking lot, and soldiers fed the three stretchers into its belly. As of late Sunday night, all three men were in good condition.
When Hughes, the No Slack commander, got around to the miserable looking young man outside the door, he didn't snap or snarl, berate or bawl. They took a little walk, and Hughes took the sharp knife from his vest and quietly snipped the black, private first-class symbols from the young man's lapels.
The investigation found the soldier had been adequately trained on the SAW and was responsible for the accident because he failed to unload the gun before cleaning it, the first step in any manual.
The report also noted he has been a good soldier with a positive attitude, motivated to learn. He may get his rank back when his battalion returns to Fort Campbell.
The dust from the Blackhawk settled, and the business of waging war returned to normal. No Slack received orders for its next mission and began the reconnaissance, searching for soldiers to shoot on purpose.