PREVOST C.
Its inventor is French: C. Prévost (around 1868) !!!
About PREVOST
I note that "our" Gustave PREVOST did not file any patent concerning a reloading tool. (Gustave Prévost - Belgium)
The only patent of this type filed in Belgium in 1868 by a PREVOST (Tire-cartouche enclume) was filed by C.PREVOST. Filed in Ixelles so more than likely by an inventor domiciled abroad (in France ???).
Unfortunately I do not have the text of C.Prevost's patent, a text that would tell us more about this inventor.
Otherwise I am leaning towards a tool patented by a Frenchman in 1868. So nothing to do with "our" Gustave. (Belgian)
MD