A farkon 1863, an tura rundunar zuwa Big Black River, inda ta tsare gada. A watan Maris, rundunar ta koma Grand Gulf, Mississippi, inda maza suka gina gine-gine, suna karfafa kariya ga Vicksburg, Mississippi. A ranar 5 ga Afrilu, 3rd Missouri Infantry, a matsayin wani ɓangare na mafi girma, an tura shi a fadin kogin Mississippi zuwa Louisiana, inda suka kafa sansanin kusa da Bayou Vidal a Tensas Parish. Ranar 8 ga watan Afrilu, ƙungiyar ta yi yaƙi a wani karamin aiki a James 'Plantation kusa da nan. Ƙoƙarin da rundunar tsaro ta yi don ta kai gagarumin hari a kan sojojin Union da ke zaune a yankin a ranar 15 ga Afrilu ya kasa lokacin da aka rasa abin mamaki ga wani hari da aka shirya. A ranar 17 ga Afrilu, zuwan jiragen ruwa na Union Navy ya tilasta wa 'yan majalisa su koma Mississippi. Sa'an nan kuma rundunar ta sake komawa ga masu karewa a Grand Gulf. A cikin
Yaƙin Grand Gulf a ranar 29 ga Afrilu, 3rd Missouri Infantry ya kare layin rami na bindigogi wanda ya shimfiɗa tsakanin manyan garuruwa biyu na Confederate. Matsayin naúrar ya ba wa maza damar yin harbi a cikin ramin jirgin ruwa na Union Navy wanda ke harbi matsayi na Confederate. Rundunar ta rasa mutum daya da aka kashe da uku da suka ji rauni a yakin. Nasarar Confederate ta hana Union Major General Ulysses S. Grant daga saukowa da karfi a wannan lokacin, ko da yake Grant ya iya saukowa da karfi a kudancin matsayi. Brigadier Janar John S. Bowen, kwamandan kwamandan a Grand Gulf, ya amsa ga saukowar Union ta hanyar aika da karfi zuwa Port Gibson, Mississippi don hana Grant.