High Quality Content by WIKIPEDIA articles! The Infantry in the American Civil War comprised foot-soldiers who fought primarily with small arms, and they carried the brunt of the fighting on battlefields across the United States. As the Civil War progressed, battlefield tactics soon changed in response to the new form of warfare being waged in America. The use of military balloons, rifled muskets, repeating rifles, and fortified entrenchments contributed to the death of many men. Generals and other officers, many professionally trained in tactics from the Napoleonic Wars, were often slow to develop changes in tactics in response.