This bayonet was designed to fit the Modelo Argentino 1879 Remington Rolling-Block Infantry Rifle.
It is very similar to the French Model 1866 Chassepot Bayonet - as are so many others - except that this bayonet has a straight blade where the French bayonet has a curved yataghan blade. The French bayonet also has a wider spine, usually inscribed - in French - with an arsenal name, month, and year of manufacture; the Argentine pieces do not boast this.
According to "Janzen's Notebook" these bayonets were also used by Uruguay.
These are extremely well-made German manufactured pieces.

Overall length - out of scabbard - is ~23-1/4";

Hilt is ~4-3/4" in length (including crossguard thickness, but not quillon), ~4" at widest point (crossguard including quillon); solid brass handle with steel furniture; no markings were found on this specimen; 14 raised ribs (15 grooves); spring-steel latching mechanism.

Straight blade is ~18-7/8" long, ~1" wide at ricasso; single fuller on both sides of the blade.
Manufacturer's mark on this specimen is "W.R. KIRSCHBAUM / SOLINGEN" and is found on the blade ricasso (right side).

Scabbards are found either brass-mounted leather or blued sheet-steel, both with ball finial.

Model 1879 (aka 1875) shown.