 On May 22, 1863, during the campaign to capture Vicksburg, Mississippi, he participated in an assault on Confederate positions that was considered a "forlorn hope", meaning the soldiers taking part in it would have little chance of surviving.Corporal Archinal was indeed one of a relatively small number of men to escape alive.Fifty-three of the survivors were eventually awarded the Medal of Honor for their participation, including Archinal and eight other members of the 30th Ohio.