Do not bother using the homing attack, as it is too hard to get to, and it is difficult to keep hitting him like that. Instead, defeat the two Black Arms soldiers and collect the guns from them. Then, go to the spring and use it. Move forward a bit so you do not start grinding the rails. Pass Black Bull in your jump, and rapidly shoot a little before you level with its eye. Repeat the strategy, and if you fill your Hero gauge, activate Chaos Control and finish him off. This is more effective and easier than to grind around him and shooting him every time around, which wastes ammunition on a lot of missed shots.