During the summer of 1952, at an OP somewhere on the MLR between OP2 and OP3 as an Artillery Forward Observer I was sitting at the trench line looking to my front, north, when a tank drove up to about 10 yards behind me. The Tank commander said that he had a number of rounds to fire and did I have any Targets? If I had I would have been firing on them with artillery, but thinking about it I had an idea. I asked him if he could ricochet a round with fuse quick to explode over a trench line running down a ridge on the south end of OP3. There were Chinese heads bobbing up and down and it appeared to have a lot of use. He said he'd try. I don't know where the first round went but the heads disappeared. On the second try the round exploded right over the trench line. We walked the shells up then down the trench line then moved northward, about NE, near the top of OP3 where I had seen activity and suspected bunkers. That tank could put them right on target, artillery couldn't pin point targets like that. Next we turned directly North. It must have been 4 or 5 miles across that valley and up the slope where there appeared to be an opening, a suspected Chinese artillery position. The tank had good range but the shell landed to the right of the target. I called to the tank commander, come left one five zero, (meaning 150 yards). I felt and heard the double blast from the tank gun but couldn't see the round hit. After searching with my field glasses a little more I turned back to the tank and the gun was pointing NW right at Panmunjom. Startled I asked why he pointed his gun that way and he assured me that he had come left 150 mils. I think that the gun was elevated enough so the shell landed outside the circle around Panmunjom, but I don't know and I never said anything about this to anyone.