sword? 19th century?

[corrado26]

Today a collector brought me this unisentified piece and wanted to know what I think it might be. May be someone here is able to tell me more about this item.
Total length 565mm, length of blade 420mm, width 55mm, central ridge with a thickness of ca. 8mm. Hilt made of two plates of horn fixed with three rivets .
Thanks
corrado26

[fernando]

Interesting piece whatever you call it, a large bayonet or a very short sword. Very important that it has a scabbard, that gives it an authentic look... and suggesting 18th century, if i may.
I wouldn't mind having it, whatever it is ;).