Interesting to see - in your third pic - chaps using 8mm Guedes M1885 rifles (second and third chaps from the left). The protruding rear of the breech blocks and the positioning of the back sights are a give away.
Yes, the M1885 Guedes rifles were made by Steyr for Portugal - but the single shot design was overtaken by developments and the rifles became surplus. They were chambered for a unique 8x60R round; some sources say the rounds were charged with black powder and others say a semi-smokeless propellent. The latter is more likely. Apparently, many Guedes were stamped with the "ZAR" marking. Here in OZ during the 1960's-70s the occasional ZAR Guedes cropped up as did the occasional Guedes round (usually headstamped for 1896).
The Guedes rifle is sometimes described as having a form of Martini action - but apart from the Guedes breech block being similarly activated by a lever, there are major design differences.
If of interest, I can post a pic of the 8x60R Guedes round vis-a-vis the 7mm Mauser and the .303" Mk,2.
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