Soulja Boy -- Charged in Porsche Gun Caper

Soulja Boy has been belatedly charged with packing heat in a car ... and the charge is a LONG time in coming.

Soulja was pulled over last January after cops stopped the car in which he was riding and discovered a loaded gun under the passenger seat. He was arrested on the spot, but the investigation took months.

The rapper claimed his neighbor was the culprit ... he had borrowed the car and stashed the Smith & Wesson .38 caliber revolver under the bucket seat of the Panamera.

So now he faces misdemeanor charges of unlawfully carrying a loaded firearm.