The M41 Walker Bulldog was named after Gen. Walton Walker who was killed in Korea. It was a 23.5 ton light tank armed with a high velocity 76mm gun. It replaced the M24 Chaffee in the U.S. Army and Army of the Republic of (South) Vietnam or ARVN. The South Vietnamese tankers liked their M41s and the type proved its worth in the invasion of Laos during Operation Lam Son 719 in 1971 when ARVN M41s met North Vietnam Army's (NVA)T54 and PT76 type tanks in the first armor battle of the war. 17 M41s destroyed 23 enemy tanks for the loss of 5 M41s and 25 M113 APCs. (Lam Son 719 did not end well for ARVN due to poor unit coordination and lack of communication. The aggressive and professional counterattack of the NVA despite horrifying losses was another contibuting factor.) Over 20 countries used this fine tank and several armies extended the service life by modifying the M41 with diesel engines, improved transmissions, and 90mm guns. A few M41s still are active in smaller countries' tank forces.