Lets say a grown man gets attacked by another grown man of roughly the same size. Neither of them are using any weapons. He fights back and stops his attacker and he stops once his attacker stops. In a case like that he should not get in trouble since he was meeting force with force, they were both grown men and they both didn't have any weapons, and he stopped once his attacker stopped. Had he continued to beat on his attacker once he stopped him then he would get in trouble since it is no longer a case of self defense if you continue to beat on your attacker once you stop them. Had he shot his attacker then he might get in trouble since he is using a greater level of force. But he is stopping once his attacker stops and he is not using any weapons so clearly it would be a case of self defense. Now obviously you can't shoot a five year old child who takes a slap at you and call it self defense, it wouldn't work for you in court, but if somebody is coming at you who is roughly your same size and you stop him without using any weapons and you stop when he stops, such as in the above example, it stands to reason you shouldn't get in trouble. It would be self defense.