The teen was playing Russian roulette at the time, according to the father of another teen present at the time.
It happened around 9:30 a.m. in the 21300 block of Greenham Dr.
The other teen's father said that he does not own a gun, and his son called him hysterical to tell him that his friend has been playing Russian roulette.
Jason Gay, a neighbor, was shocked to hear what unfolded not too far from his home.
"This morning I thought I heard two gunshots. I didn't pay no mind to it until I saw the helicopters," said Gay.
The teen was taken to the hospital in grave condition.
Detectives are investigating where the weapon may have come from.