 The Army used all types for either training or testing within the United States, but intended the M4A2 and M4A4 (with the A57 Multibank engine) to be the primary Lend-Lease exports.Shermans were being issued in small numbers for familiarization to U.S. armored divisions when there was a turn of events in the Western Desert campaign.Axis forces had taken Tobruk and were advancing into Egypt and Britain's supply line through the Suez Canal was threatened.