Buddy --
First place to look is Burke's Confederate military service file for Co. "H", 12th Mississippi Regiment.
Have you seen the documents in his file yet?
At Manassas this regiment was assigned to Robert E. Rodes' Alabama Brigade. On General Johnston's orders, the army left their camps at Manassas on March 7-8, 1862. On May 31, 1862, the regiment lost 191 killed and wounded at Seven Pines, Va., among the highest casualty rates reported during the war.
Shortly after Seven Pines the 12th Mississippi was assigned to Brig. Gen. Featherston's Mississippi Brigade, which later served under Carnot Posey. Losses during the Seven Days Battles were 225 killed, wounded and missing. The brigade had a notable role in all the battles of the Army of Northern Virginia, right down to the last ditch in the fighting at Fort Gregg.
I have inspection reports for this brigade dating Aug. 30th and Sept. 30th 1864.
To determine what part John C. Burke played in the history of this command, you really must know what's in his service file. These can be ordered by licking on the link at the top of this page and entering information about the soldier and his command.