===Third Organization===
The consolidation of Arkansas Post units when they reached the Army of Tennessee at Tullahoma Tennessee created supernumerary (excess officers without official assignment) officers who returned to the Department of the Trans-Mississippi. It seems that Captain Hart fell into this category and this explains his eventual return to the Department of the Trans-Mississippi. After being exchanged in May 1863, Hart likely moved from Virginia to Tullahoma with the remnants of the battery and then made his way back across country and across the Mississippi River to rejoin confederate forces in the Department of the Trans-Mississippi.
Exactly when the third organiztion of Hart's batttery occured is unclear. There are few references to Hart’s Battery during the last year of the war and there are no surviving muster rolls from the third orgainzation. On February 25, 1864, Hart and another former battery officer, Lieutenant William T. Tiller were in Houston Texas. Lieutenant Tiller had made application to become a Cadet, (a type of officer in training) in the Confederate Army, and Captain Hart provided a letter of recomendation. This may indicated that Lieutenant Tiller and Captain Hart were still considered supernumary (excess) officers. Lieutenant Tiller eventually joined Captain O. G. Jones Company of Texas Light Artillery as a second lieutenant. The National Archives, Publication Number: M322, Publication Title: Compiled Service Records of Confederate Soldiers Who Served in Organizations from the State of Missouri, Content Source: NARA, National Archives Catalog ID: 586957, National Archives Catalog Title: Carded Records Showing Military Service of Soldiers Who Fought in Confederate Organizations , compiled 1903 - 1927, documenting the period 1861 – 1865, Record Group: 109, State: Missouri, Short Description: NARA M322. Compiled service records of Confederate soldiers from Missouri units, labeled with each soldier's name, rank, and unit, with links to revealing documents about each soldier., Roll: 0081, Military Unit: Hart's Battery, Light Artillery AND Key's Battery, Light Artillery, Accessed 17 January 2014, http://www.fold3.com/image/219842222/?terms=Charles#20/219846038/
The first mention of the thrid organization of Hart's Battery is in General E. Kirby Smith’s September 30, 1864 report on the organization of the Army of the Trans-Mississippi Department. Hart's Battery is listed as belonging to the Siege Train. United States. War Dept. The War of the Rebellion: A Compilation of the Official Records of the Union And Confederate Armies. Series 1, Volume 41, In Four Parts. Part 3, Correspondence, etc., Book, 1893; digital images, (http://texashistory.unt.edu/ark:/67531/metapth145055/m1/971/?q=Etter Arkansas Battery : accessed July 17, 2013), University of North Texas Libraries, The Portal to Texas History, http://texashistory.unt.edu; crediting UNT Libraries Government Documents Department, Denton, Texas. On November 19, 1864, General E. Kirby Smith, commanding the Confederate Trans-Mississippi Department, issued Special Orders No. 290, re-organizing the artillery of the department and for the first time providing numerical designations to the batteries and battalions. In this reorganization, Hart's Battery, armed with four mounted guns, and commanded by Capt. William Hart was re-designated as the 2nd Arkansas Field Battery and assigned to the Reserve Battalion. Edward G. Gerdes Civil War Page, Organization of the Artillery in 1864, Accessed January 30, 2011, http://www.couchgenweb.com/civilwar/artillry.html United States. War Dept.. The War of the Rebellion: A Compilation of the Official Records of the Union And Confederate Armies. Series 1, Volume 41, In Four Parts. Part 4, Correspondence, etc., Book, 1893; digital images, (http://texashistory.unt.edu/ark:/67531/metapth145061/m1/1064/?q=Hart : accessed December 16, 2013), University of North Texas Libraries, The Portal to Texas History, http://texashistory.unt.edu; crediting UNT Libraries Government Documents Department, Denton, Texas.
On April 1, 1865, General Orders No. 31, Headquarters, Trans-Miss Department, was published at Shreveport, LA, which listed the conviction of Private John T. Sharman, and Private E. W. Glenn, of ''Knowing of an intended Munity and not giving Information thereof to the Commanding Officer''. The two were sentenced to bread and water, wearing a twenty-four pound ball and chain and hard labor. The National Archives, Publication Number: M317, Publication Title: Compiled Service Records of Confederate Soldiers Who Served in Organizations from the State of Arkansas, Content Source: NARA, National Archives Catalog ID: 586957 National Archives Catalog Title: Carded Records Showing Military Service of Soldiers Who Fought in Confederate Organizations , compiled 1903 - 1927, documenting the period 1861 – 1865, Record Group: 109, State: Arkansas, Short Description: NARA M317. Compiled service records of Confederate soldiers from Arkansas units, labeled with each soldier's name, rank, and unit, with links to revealing documents about each soldier. Roll: 0039, Military Unit: Hart's Battery, Light Artillery AND Key's Battery, Light Artillery, Givenname: John T, Surname: Sharman Age: [Blank], Year: 1865, Surname Starts With: S, Accessed 13 December 2013, http://www.fold3.com/image/219835664/?terms=Hart#20/219843332/