Ok. Then I would suggest begin by apologising for hitting him. Explain why what he was doing was dangerous.
Maybe you could then ask him to tell you how he feels about you now. Listen to him and then, when he has finished say, "Well, ds2 feels that way about you because of the things you do to him." and ask him to think about that, that other people may feel about him what he is currently feeling about you. Ask him how it makes him feel to know other people think bad things about him.
You could tell him that it is normal for brothers to argue but physically fighting, or bullying is not acceptable. Have a chat about things he could do to calm down - get him to think about it, and come up with ideas (going into the garden, into the bedroom, turning on the tv etc) and agree strategies.
And then come the consequences.
You could finish by saying that today is a new start. That you rely on him, as older brother, to take charge and lead with a good example. From now on, any bullying or violent behaviour will result in loss of for X days.
Don't know if any of that sounds any use.
I just have to stick the hoover on when ds1 is kicking off and he legs it to his room.