In 1951 it was decided to turn the program into a heavy tank project with an even larger 120-millimetre (4.7 in) tank gun; though three prototypes were built, this too was abandoned in 1956, mainly due to a failure to design a powerful enough engine.
1951. godine odlučeno je da se program uklopi s projektom razvoja teškog tenka s još većim 120 mm tenkovskim topom; iako su napravljena tri prototipa, ovaj projekt je također napušten 1956. godine, uglavnom zbog neuspjeha u razvoju dovoljno jakog motora.