Based on just the two photos you posted (we need more), it appears to be what we Militaria collectors call a "mixed marriage" relic. That means, it is composed of (at least) two parts from relics which did NOT originally go together. In your case, it appears to have a cavalry sword's blade stuck into a saber-bayonet's brass handle. That type of handle has a ring-shaped brass section above the curved "J" at the front of the handle, and the rifle/musket's barrel fitted through that ring-shaped section. It seems to have been bashed down somewhat on your handle. As I said, we need more photos to be sure about what it is.