@Low: yeah I know it's that dust thing :P But like I said in my edit, I have yet to see it do significant damage to anyone powerful, since apparently the old man didn't feel like using it against Madara when he had his Susanoo on. If it can do what you say, it would pierce Susanoo without a problem
Again, while the Gudou Dama is effective against people with chakra based attacks, the Magma Missiles are not chakra based. They'd destroy his black ball shield, and him along with it. Think of it, since there's no chakra behind it, as a giant physical blast. The bijuu dama are purely based on chakra, so no matter what they do it's ineffective.