It was built by removing the turret of the R-2 light tank (Panzer 35(t)) and building a pedestal to mount a Soviet 76.2 mm (3.00 in) ZiS-3 field gun in its place.

It was decided to convert them to tank destroyers on the model of the German Marder II and Romania's own TACAM T-60, still in development.

[3] Leonida began work in late February 1944, and the first batch of twenty conversions was complete by the end of June.

Production was halted then because the gun was thought inadequate to face the new heavily armored IS-2 tanks being fielded by the Soviets.

After 23 August coup, a company of twelve was assigned to the Niculescu Detachment when it was rushed north at the beginning of September to defend the Transylvanian frontier against the Axis counterattack from Hungary.

This was successful and the Armoured Group was disbanded when the joint Soviet-Romanian forces pushed the last Axis units out of Romanian territory on 25 October 1944.

The Soviets immediately seized most of the TACAM R-2s in exchange for a few captured German tanks, but two were reported as operational on 31 March and two were still on hand on 24 April.