Kammala jumla mai zuwa: Da yake shiga aikin soja a lokacin yakin basasa a lokacin rani na 1862, Buck ya shiga ranar 17 ga Agusta a Windsor, Connecticut, kuma an tattara shi a matsayin mai zaman kansa tare da Kamfanin A na 21st Connecticut Volunteer Infantry. Da farko an sanya shi ga Sojojin Tarayyar Potomac, shi da abokansa 21st Connecticut Volunteers sun yi yaƙi a yakin Fredericksburg daga Disamba 12 zuwa 15 na wannan shekarar. Yayinda yake aiki a "Mud March" na Burnside, an ba Buck girma zuwa matsayin dan jarida a ranar 20 ga Janairu, 1863. Shi da rundunarsa sun shiga cikin Siege na Suffolk a wannan bazara, mai kula da tsaro a kusa da Portsmouth da Newport News a lokacin rani, kaka da hunturu. Wani ɓangare na ƙungiyar ta Union tare da James River na Virginia, wanda aka kaddamar a ƙarshen Janairu 1864, 21st Connecticut Volunteers sannan ya wuce ta Fort Powhatan da Smithfield kafin ya tafi Arewacin Carolina, inda suke aiki a New Bern (Fabrairu 12), Plymouth, Washington da Blount's Creek kafin ya koma Portsmouth, Virginia a ƙarshen Afrilu. An haɗa su da dakarun Tarayyar da ke cikin ayyukan da aka yi a kan Petersburg da Richmond don yawancin bazara da rani, sun shiga cikin Swift Creek, Fort Darling, da
Yaƙin Drewry's Bluff, Bermuda Hundred, da White House kafin yaƙi a yaƙe-yaƙe kusa da Cold Harbor don yawancin watan Yuni da kuma yakin basasa a Bermuda Hundred daga ƙarshen Agusta zuwa ƙarshen Satumba 1864.