Central African sickle knife/Ngombe Bero.

[Luc LEFEBVRE]

You're right the bero are battle swords.It is probable also that these knives were occasionnaly thrown.
3 bero from my collection:
The first is rare with the spur just below the handle, and old XIXeme, the others beginning of the XXeme.
Nzombo, Lobala, Ngbaka, Ngbandi, Ngombe. From CONGO between Congo and Ubangi river.

Luc