It happened at about 4:15 p.m. at the Colony Place Apartments in the 2100 block of Hyde Place in Fayetteville.
Police say their preliminary investigation shows that Jaylean Richardson was in a back room of his grandparent's apartment when a rifle went off.
Police haven't said if Jaylean was playing with the weapon, and it went off, or if he dropped the weapon and it fired.
Jaylean was rushed to Cape Fear Valley Medical Center where he was later pronounced dead.
Police have charged Jaylean's grandfather, 52-year-old David Nathaniel Richardson, with involuntary manslaughter and failure to secure a firearm.
David Richardson has been processed at the Cumberland County Detention Center and received a $6,000 secured bond.