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I suspect that these are either 7x57mm Mauser, or maybe 7.65x54mm Mauser (most probably the 7mm). They were made by Deutsche Metallpatronenfabrik, of Karlsruhe (who later became DWM). The FyA stands for Fusils y Ametralladores (rifle and machine guns), and indicates that they were probably made on contract for a South American country.
They look like they have the short cases, which were altered from 7.65x54 Cases to chamber in a 7x57 Mauser rifle. These are known as 7mm Kortneck (Short neck). They were made using cases DWM had available at the time. They are said to have worked fine in 7x57 chambers, although problems did arise after returning to firing standard 7x57 rounds. This is apparently because the chamber in front of the shortened neck was eroded by hot gas produced on firing, which would cause it to become worn, which would cause a normal length case to stick when the bolt was opened.