There's unlikely to be a schematic if you didn't find one on a quick google search. There were lots of small makers in the Eibar region.

8mm Lebel revolver (8mm French Ordnance) is available sporadically from Prvi, and several custom loaders including Reed's Ammunition and Research. It's a fun cartridge to shoot, about on par with .32 long. I have both a French 1893 and a Belgian pocket revolver that shoot it, and about 5 boxes on hand.