Nobody uses the MG core for it's magnetic effect. It's not as great as the HMC, but it's a staple part for any other combo that's bearing/shaft free. It's the second heaviest SG with a core.
Nobody would use a plastic against a MFB.
Quote:because the MFB beyblades are just far heavier naturally, being made from a higher percentage of metal.
Nobody would use a plastic against a MFB.