Tuhia he tomokanga mō tēnei wāhanga - I uru atu a Gilbert ki te ope tūao i muri i te nuinga o ōna hoa, i te Oketopa 1862. Heoi, i tohua ia hei koroneela o te 27th Iowa Volunteer Infantry Regiment i te Oketopa 3, 1862. I uru te rārangi o Gilbert ki te haerenga a Frederick Steele ki Little Rock
engari kaore i uru ki tetahi whawhai. I tukuna ia ki te mahi hoia i Arkansas, katahi ka whakawhiti ki Mississippi i reira i honoa ai tana rerenga ki te wehenga a Andrew J. Smith i te XVI Corps i te haerenga a Meridian.