It happened just after 11 p.m. Wednesday in the 3300 block of Old Nash Road in the Middlesex area.
When deputies arrived, they said they found 21-year-old Taylor Michael Samonia with a gunshot wound to his left side and people administering CPR.
When EMS got there, it was determined that Samonia had died.
Detectives said their investigation shows 27-year-old Daniel Wayne Griffin was attempting to reload a handgun when it went off, hitting Samonia.
The sheriff's office said it conferred with the district attorney before filing the involuntary manslaughter charge.