Marietta police said in a statement that Daryus Johnson of Marietta was found unconscious on the floor of an apartment on Bentley Road Tuesday. He later died.
Police said Johnson and 19-year-old Elyjah Marrow had been handling the handgun when it accidentally discharged.
Marrow faces charges that include involuntary manslaughter; reckless conduct; and possession of a stolen firearm. He was being held in the Cobb County Jail. Jail records do not indicate whether he has an attorney.