Part of the answer depends on which edition of the "Tishomingo Rangers" you have in mind. The first "Tishomingo Rangers" organized under Captain William M. Inge at Corinth MS on Feb. 20, 1861. John K. Duncan was elected 1st Lieutenant of this company. According to papers in one of Inge's military service files, the company was not called into Confederate service, and he left to become adjutant of Col. Griffith's 12th Mississippi Regiment in Virginia. Duncan may have assumed command of this state company after Inge's departure, but we have no record of this. Evidently members joined other companies then entering service, so the "Tishomingo Rangers" disbanded.

The "Tishomongo Rangers" reorganized for twelve months in Confederate service, enlisting at Iuka MS on Nov. 14, 1861. At this time Philip D. Roddey was elected captain, Duncan again being 1st Lieutenant of this company. Roddey's "Tishomongo Rangers" was assigned to Major Charles Baskerville's 4th Mississippi Cavalry Battalion as Company "D" but never served with it. The remaining five companies under Baskerville's command were assigned to Brewer's 2nd Mississippi-Alabama Battalion on March 28, 1862. Lt. Col. Brewer asked that Roddey's company be ordered to report to him, but it remained in independent service through September of 1862.

About Oct. 1, 1862, the "Tishomingo Rangers" reorganized as two companies, the first under Captain Richard W. Johnson, the second under Captain James T. Williams. They became Companies "H" and "I" of Roddey's 4th Alabama Cavalry Regiment. I don't find any record of Duncan serving with either company. There is a parole for J. N. Duncan, 1st Lieut., Co. "E", 2nd Mississippi Cavalry, but he may be a different officer.