The 17th Indiana Volunteer Regiment was part of “Wilder’s Lightning Brigade”, a mounted infantry brigade under Col. John T. Wilder. Through his efforts he mounted his infantry on horseback and equipped them with Spencer Repeating Rifles. This paper argues that these changes were deliberate on the part of John T. Wilder rather than emulating others, led to a conscious and noticeable change in tactics, that these changes were effective, and examines the Brigade’s influences on future military tactics. Through the use a various Primary and Secondary sources, with heavy emphasis placed on diaries, letters, unit histories, and drill manuals, I show that the changes made were deliberate, noticed by the men and their adversaries, highly effective, and an early example of future forces like mechanized infantry.