CREATE TABLE table_31149 ("Name/ designation" TEXT, "Year of intro" FLOAT, "Country of origin" TEXT, "Primary cartridge" TEXT, "Major users" TEXT)

Who are all the major users of the Gordon Close-Support Weapon System?
SELECT "Major users" FROM table_31149 WHERE "Name/ designation" = 'Gordon Close-Support Weapon System'
SELECT "Major users" FROM "table_31149" WHERE "Name/ designation" = 'Gordon Close-Support Weapon System'