This is right out of the PA Game Digest of prohibited acts on state game lands...
Target shoot with firearms, bows and arrows, or devices capable of launching projectiles in a manner that could cause injury to persons or property, or on areas posted closed to those activities.
So my take on it is if you are doing it safely, and not shooting at and damaging live trees, you should be good to go. And as Jerry said, throw your hunting license on your back and you are legally hunting coyotes.