Thanks, Eswube! (I am trying to find a good photo of the polish Browning MG, a sound weapon, very appreciated by both sides in the SCW).
The MG-13 was a design of L. Schimeisser, who called it "Dreyse" for the inventor of the famous prussian neddle rifle. It was a short recoil operated, belt fed, water cooled and tripod mounted medium machine gun. After the end of WWI, the Dreyse MG was modified by the Simson company at Suhl and emerged as a magazine fed and air cooled LMG:
It was the standard Germán LMG until the introduction of the mighty MG-34. It was sold to Portugal, to the RoC (as the armament of the Pz. I) and to the francoist forces during the SCW. Cheers.
P.S. I was searching for a suitable image hosting, and I found Postimage. May I ask your opinion about this host? Any other suggestion? Thanks!
P.S of the P.S: Thanks, Char and Pantsu for the ideas for shading the round parts.