The United States supplied the South Vietnamese Army with surplus stocks of M1945 load carrying equipment early in the war. Unfortunately the combat field pack proved to be too small for multi-day missions and old larger French rucksacks were often preferred instead. In addition the pack's attachment to the suspenders was so poor that when it was employed ARVN soldiers routinely carried the pack on a separate set of shoulder straps. As a result of these deficiencies Natick Labs developed the ARVN rucksack.11. Report on Individual Clothing And Equipment for Indigenous Forces In Southeast Asia - Phase 1 (U.S. Army Natick Laboratories 8th May 1963)