Montgomery was with three friends, aged 19, 18 and 16, on Friday night when they decided to play the deadly shooting game.
The teens were sitting on the back porch of Montgomery's home when the fatal shot was fired.
Montgomery was the first to hold a loaded .38 caliber handgun to his head and pull the trigger.
The teenager collapsed in front of his horrified friends who called paramedics.
Montgomery was airlifted to the hospital where he later died from his injuries.
A spokesman for Pinellas County Police said the investigation was continuing and they were focusing on how the teens obtained the gun.