See the 3rd post. The gun was proved in 85' and again in 86' when the Proof House was still using crushers. It was proved then under the 54' - 89' Rules at 900 Kg/cm2 for a service pressure of about 9500 psi by transducers.
Starting in 1989 it would have been proved per CIP at 850 BAR for a max. service of about 10,700 psi by transducers.