Ah... its a Korean designed M-1978 (KOKSAN) 170mm self propelled (SP) gun?
The M-1978 (KOKSAN) 170mm self propelled (SP) gun, of North Korean design and manufacture, is probably mounted on a T-54 chassis, a Chinese Type 59 hull or a T62 Chassis. The 170mm gun has no superstructure, and it has 2 large spades at the rear. The 170mm (~6.69") gun itself is a previously unknown type, possibly Russian coastal-defence or ex-naval weapon. The M-1978 Koksan gun was first noted publicly in a parade in 1985. The Koksan is named after the city in North Korea where it was first seen by the West in 1978. The M-1978 version carried no on-board ammunition supply.