Complex sentence: Oswald was court-martialed after accidentally shooting himself in the elbow with an unauthorized.22 handgun, then court-martialed again for fighting with a sergeant who he thought was responsible for his punishment in the shooting matter.
Split into simpler sentences: Oswald was court-martialed after he accidentally shot himself in the elbow with an unauthorized.22 handgun. He was court-martialed a second time for fighting with a sergeant who he thought was responsible for his punishment in the shooting matter.