His command, the 12th Louisiana, likewise did not endure the siege of Vicksburg having fled East to Jackson, Miss. following the Battle of Champion's Hill, May 16.
It is not at all clear from the records that John remained in the hospital during the 47 day siege, or may have been discharged from the hospital and temporarily assigned to another unit and subsequently killed while within the siege lines.
John W. Hammock, Private, Company E, 12th Louisiana Infantry, enlisted November 12, 1861 at Columbus, Kentucky by Col. Scott for 12 months, left sick in Vicksburg May 10, 1863 where he died during the siege, "died of wounds received in action," July 6, 1863, description: born in Ala. Perry Co., blue eyes, black hair, fair complexion, 5' 9", 22 year old Farmer
M320: Compiled Service Records of Confederate Soldiers Who Served in Organizations from the State of Louisiana
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Hammack, J. W., Co. E, 12th Louisiana, died 1 July 1863, buried Cedar Hill Cemetery, Vicksburg City Cemetery
Confederate Soldiers Buried at Vicksburg
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12th Regiment, Louisiana Infantry
12th Infantry Regiment completed its organization at Camp Moore, Louisiana, in August, 1861. Its companies were from the parishes of Caldwell, Claiborne, Vermilion, Cameron, Calcasieu, Jackson, Ouachita, Bossier, and Iberia. Sent to Missouri, the unit was captured at Island No. 10 in April, 1862. After being exchanged, it was assigned to Rust's, Buford's, T.M. Scott's, and Lowry's Brigade. It fought at Champion's Hill and Jackson before participating in the campaigns of the Army of Tennessee from Resaca to Bentonville. In July, 1862, the unit contained 41 officers and 546 men, reported 11 killed, 57 wounded, and 5 missing out of the 318 engaged at Peach Tree Creek, lost many during Hood's Tennessee Campaign, and surrendered with only a remnant on April 26, 1865. Its commanders were Colonel Thomas M. Scott; Lieutenant Colonels James A. Boyd, Wade H. Hough, Noel L. Nelson, and Thomas C. Standifer; and Majors John C. Knott and Henry V. McCain.
NPS Soldiers & Sailors System