You can reach the other side of a hill with a ballistic trajectory from just about any deck gun, but the Zumwalt will have some extra reach:
"The Advanced Gun System is a 155 mm naval gun, two of which would be installed in each ship. This system consists of an advanced 155 mm gun and the Long Range Land Attack Projectile. This projectile is in fact a rocket with a warhead fired from the AGS gun; the warhead weighs 11 kg / 24 lb and has a circular error of probability of 50 meters. This weapon system will have a range of 83 nautical miles (154 km) and the fully automated storage system will have room for up to 750 rounds."
Naval gunfire is known for it’s flat trajectory.