Whatever case you use:
250 (more or less) grain bullets, either full or semi wadcutter. You want a sharp edge to "grap" the pin and fling it good when hit. Moderate velocities should do. 800 to 1100 fps will do nicely. As the lower the velocity, the better the recovery, I'd start lower.
Make sure your gun is sighted in for the ammo at the distance in question. Hold for the biggest middle of the pin.
Supply a report, will you?