Fortifications
There were 23 batteries installed on Corregidor, consisting of 56 coastal guns and mortars. In addition, Corregidor had 13 anti-aircraft artillery batteries with 76 guns (28 3-inch and 48 .50-caliber) and 10 60-inch Sperry searchlights.
The longest-range coastal pieces were the two 12-inch (305 mm) guns of Batteries Hearn and Smith, with a horizontal range of 29,000 yards (27,000 m). Although capable of an all around traverse, these guns, due to their flat trajectories, were not effective for use against targets on Bataan.
During the siege, the island had ample armor-piercing ammunition but very little of the anti-personnel type, which then was of greatest demand for use against land targets on Bataan. In fact, most of the anti-personnel shells were only for the 12-inch mortars of Batteries Way and Geary.
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