Their finest hour came in the Battle off Samar, when Taffy 3, a task unit composed of six of these ships and their screen of three destroyers and four destroyer escorts gave battle against the Japanese main force. Their desperate defense not only preserved most of their own ships, but succeeded in turning back the massive force with only aircraft machine guns, torpedoes, depth charges, high-explosive bombs, and their own 5"/38 caliber guns. Tasked with ground support and antisubmarine patrols, they lacked the torpedoes and armor-piercing bombs to tackle a surface fleet alone. Taffy 3 was to be protected by Admiral Halsey's Third Fleet with carriers and battleships. But the Third Fleet had left the scene to pursue a decoy carrier fleet, inadvertently leaving Taffy 3 the only force between the massive Japanese fleet and undefended landing forces at Leyte Gulf. The lightly armed vessels each had only one 5-inch/38 cal gun mounted aft, yet two of their number, "St. Lo" (ex-"Midway") and , became the only US aircraft carriers to ever record a hit on an enemy warship by its own guns. "St. Lo" hit a Japanese destroyer with a single round and "Kalinin Bay" damaged a with two hits. Recent evidence suggests that six 5-inch shells fired from struck the cruiser "Chōkai". One of these rounds was reported to have impacted amidships on the starboard side, causing a large secondary explosion (probably from one of "Chōkai"s own torpedoes) that proved fatal to the heavy cruiser. The "White Plains" gun crew claimed to have put all six 5-inch rounds into "Chōkai" from a range of , near the maximum effective range for the 5-inch/38 gun. However, this claim is not supported by Japanese sources, which report this damage as resulting from an air attack.