CREATE TABLE table_204_343 (id DECIMAL, "nation" TEXT, "model" TEXT, "length" TEXT, "barrel length" TEXT, "weight" TEXT)

what country has the least number of rifles in service ?
SELECT "nation" FROM table_204_343 GROUP BY "nation" ORDER BY COUNT(*) LIMIT 1
SELECT "nation" FROM "table_204_343" GROUP BY "nation" ORDER BY COUNT(*) NULLS FIRST LIMIT 1