By the outbreak of the Civil War, 29 year old August was living in Dalton, Georgia. He was an expert mechanical draftsman, pattern designer and maker. In addition he was also an accomplished musician and excelled as a cornetist. By the Spring of 1861, he had joined the elite Dalton Militia company known as the Dalton Guards. In early June 1861 the company journeyed to Camp McDonald at Big Shanty, Ga to join the newly formed 4th Georgia State Brigade under command of State Brigadier General William Phillips. This brigade was eventually disbanded about the end of July and it's rifle and cavalry battalions were joined to become the Phillips Legion under now Confederate Colonel William Phillips. The Dalton Guards became Company B in the Infantry Battalion. August's records at this time show him as a private so it is unclear whether or not he was performing musician's duties yet.
After a grueling winter campaign in the mountains of western Virginia, the Legion was sent to the South Carolina coast in January 1862 to rest, recruit and refit. During this period it was determined to form a formal Legion band and on May 1st 1862, the musicians of the various infantry companies were transferred to the Legion's Staff under the direction of newly appointed Bandmaster, August Rauschenberg. Regimental Bands in the Civil War performed in multiple roles. At reviews or on other ceremonial occasions the band would perform in it's musical function. At other times while in camp, the band would conduct concerts. On the march, the band would play to liven the tedium and keep the men's spirits up. Franz wrote of one musical occasion that he dreaded having to perform. In a letter written home on April 12th 1864 he wrote, "Yesterday I had a very painful duty to perform. A Private of our Brigade, 24th Ga. Regiment, was shot for desertion and I had to play a Dead March from the Guard House to the place of execution. It was a very solemn and affecting scene. The prisoner seemed willing to die, he was firm and resigned, and received the fatal bullets fired by his countrymen like a man. God grant I may never witness another such spectacle." Research into Confederate Court Martial records reveals the identity of this unfortunate soldier to be Private W H Tanner of the 24th Georgia's Company K.
On occasions when the Legion was going into battle, the musicians would put away their instruments and serve as stretcher bearers, carrying wounded soldiers to field hospitals located close by.
August served through the entire war until captured with most of the Legion Infantry at Sailors Creek on April 6th 1865. He was imprisoned at Newport News, Virginia until his release on June 24th 1865. His Oath of Allegiance describes him as being five foot six inches tall with light hair, light complexion and gray eyes. Shortly after his release, 34 year old August married Miss Annie Elizabeth Kanerian in Richmond, Va. They returned to Georgia and spent the remainder of his life in productive and creative pursuits, mostly in Atlanta. August passed away on March 14th 1911, outliving all of his siblings by many years.