The CN 105-57 is a light 105 mm rifled tank gun originally designed to be mounted on light tanks with oscillating turret such as the French AMX-13 and the Austrian SK-105 Kurassier.

[2] Other changes to the gun include a horizontal breechblock, a muzzle brake, and a single-cylinder recoil mechanism together with a single hydropneumatic recuperator.

The 105 mm L44/57 FTR gun produced in Argentinema at the Fábrica Militar «Río Tercero» (FM «RT»), Río Tercero, Córdoba, which was a copy of the French CN-105-57 gun.

The modification enables the weapon to fire the 105 mm OFL 105 G1 APFSDS ammunition.

The ordnance is fitted with a new single baffle muzzle brake, a thermal sleeve, a fume extractor and semi-automatic horizontal breech mechanism.