A California court rules that there’s no Second Amendment protection for someone carrying a “billy.” In this case a baseball bat with a hole hollowed out and a bolt put through it, presumably for bashing in skulls with greater ease than one can accomplish with hickory alone.
Instead, it appears to us to be a weapon which, by its very nature, increases the risk of violence in any given situation, is a classic instrument of violence, and has a home-made criminal and improper purpose. Likewise, it appears to be the type of tool that a brawl fighter or a cowardly assassin would resort to using, designed for silent attacks, not a weapon that would commonly be used by a good citizen.
This strain of thinking has a long history among the courts in interpreting the right to keep and bear arms. There’s always been a strong bias against the types of weapons you might find wielded by the lower classes.