A female cop is getting canned after accidentally shooting a man with his own gun during a traffic stop in Florida -- and it's all caught on graphic body cam.

Jason Arrington is fully cooperating in video just released from the Jacksonville Sheriff's Office, calmly telling an officer he has a gun on him, after he was pulled over for running a red light. He steps out of his SUV and 2 officers frisk him ... that's when Officer Mindy Cardwell removes the weapon from Arrington's waistband, and it suddenly fires.

Chaos unfolds immediately -- another officer tells Caldwell to drop the pistol as he helps the wounded Arrington to a nearby patch of grass, blood seeping through the man's pants.

The bullet tore through Arrington's upper thigh, exiting his inner leg and causing a dangerous arterial bleed -- but officers stopped the bleeding quickly with a tourniquet.

Arrington -- who's legally permitted to have a gun -- is expected to make a full recovery, but he's now suing over the December incident, saying he's left with lasting injuries that have messed with his ability to work as a crane operator.

An Internal Affairs investigation sealed Caldwell's fate -- the department is moving to fire her. Officials found she struggled to remove Arrington's gun from its holster and she accidentally put multiple fingers inside the trigger guard, causing it to go off.