ARMOR-CAVALRY: Part 1; Regular Army and Army Reserve/Korean War
- When North Korea suddenly attacked the Republic of Korea on 25 June 1950, the U.S. Army was weak in tanks, and its units initially entered combat in Korea without them. The 7th, 24th, and 25th Infantry Divisions and the 1st Cavalry Division (organized as infantry), all on occupational duty in Japan, had assigned to them the 77th, 78th, 79th, and 71st Tank Battalions, respectively. But only one company (A) of each battalion had been organized, and those companies had only M24 light tanks. Heavier tanks, it was feared, would damage Japanese roads and bridges.
- Although the rugged terrain in Korea had been considered generally unsuitable for tank employment, Russian-made T34's were used with success by the North Koreans during the early days of the war. American tanks were rushed to the scene in support of the United Nations and engaged in their first combat on 10 July. For several weeks they were outnumbered, and it was not until late August that the tank balance in Korea was tipped in favor of the United Nations. By then more than 500 U.S. tanks were in the Pusan Perimeter, outnumbering the enemy's there by over five to one. Far the remainder of the war, tank units of battalion size and smaller were in most combat actions.
- Tank battalions in the early Korean fighting of July and August 1950 were the 6th, 70th, 72d, 73d, and 89th, averaging 69 tanks each. The 6th was equipped with M46 Pattons; the other battalions were about equally divided between M26 Pershings and M4A3 Shermans. The 64th Tank Battalion entered the war in early November 1950 with the 3d Infantry Division.
- No armored divisions were sent to Korea, although six armored divisions, the 1st, 2d, 3d, 5th, 6th, and 7th, were soon active. Actually only two, the 1st and 2d, were organized as armored, the others being principally training organizations, and only the 2d went overseas, going to Germany in 1951.
- The armored division strength and organization were little changed by a TOE of late 1952, but its tanks, totaling 343, mounted more powerful guns. One battalion was authorized 69 heavy tanks (T43's, which later became M 103's ) with 120-mm. guns, the heaviest weapon yet carried by an American tank. Weighing approximately sixty tons and carrying a crew of five, the T43 was the largest and most powerful tank that had been produced by the United States. Three battalions of the division each had 72 mediums (M47's) with 90-mm. guns, and the reconnaissance battalion had 30 light tanks ( T41E1's) mounting 76-mm. guns. The new model light tank was a modified version of the T41, and was christened the "Walker Bulldog" in early 1951 in honor of Lt. Gen. Walton H. Walker, killed in the Korean War. An additional 28 light tanks were dispersed within the division- 3 to each combat command and to the division headquarters company and 2 to each tank and armored infantry battalion.
- In mid-1952 a new medium tank, the M48, also named the Patton, was introduced. With an improved fire control system, it was proclaimed to be capable of more first round hits than any other American tank yet built. Weighing 45 to 50 tons and armed with a high-velocity 90-mm. gun, the new medium had a crew of four-one less than its preceding model.
- The activation in 1951 of the 11th Armored Cavalry brought the total active regiments of this type to five for the Korean War period, but none served in the Far East. The other four active regiments were the 2d, 3d, 6th, and 14th. The primary role of the armored cavalry regiment was described in 1951 as being "to engage in security, light combat, and reconnaissance missions. The regiment is not designed to engage in combat with hostile armor or strongly organized defenses."
- Many Army National Guard units went into Federal service during the Korean War. Eight N.G. infantry divisions were called in, and organic to each were a tank battalion and a reconnaissance company. The 40th Infantry Division (California) and 45th (Oklahoma) fought in Korea; the 28th (Pennsylvania) and 43d (Connecticut, Rhode Island, and Vermont) went to Germany; and the 31 st ( Alabama and Mississippi), 37th ( Ohio ) , 44th ( Illinois ) , and 47th ( Minnesota and North Dakota) became training organizations for individual replacements for the Army. Other National Guard units entering Federal service brought N.G. units mobilized to approximately one-fourth of the total number organized and federally recognized.
- Early in the war the period of service was set at 21 months; later it was extended to 24 months. In August 1952 when it became obvious that two years would not see the end of the war, Congress- disturbed that many areas of the country had sent most of their Guard units into service and had few at home stations- passed legislation to provide for the organization of corresponding National Guard units. These units would bear the same designations as those in the service, with the addition of "( NGUS )" after their designations. This arrangement permitted the states and territories to organize units, and to assign men returning from duty with a unit in Federal service to its counterpart in the National Guard. Maximum Federal service for Guard units (not personnel) was fixed at five years, and as the units reverted to state or territory control, the corresponding NGUS units were dropped.
- Generally the system worked as planned, but in a few instances it did not. The NGUS units in some states or territories were not organized in the same geographical areas as their counterparts and hence were not historical continuations of them. Other units, upon release from active military service, were not relocated in their former areas. In both instances, significant factors were the continuing changes in Department of the Army mobilization requirements for National Guard units and changes in the organizational structure for Regular Army units that were also applied to the National Guard.
- Although the Korean Armistice Agreement of 27 July 1953 ended largescale combat in Korea, military forces were still required in positions of readiness.