David - "Lady Richardson" was the 3.67-inch (20-pounder) Parrott rifle captured at Corinth in October, 1862. Its mentioned (by name) as at Ft. Pemberton (by Col. C.A. Fuller) in late March, 1863, under command of Lt. Lambert 22d Louisiana; on 15 June,'63 two 3.67" Parrotts are under command of Lt. Quisenberry, also of 22d Louisiana, one of which was "Lady Richardson" according to pretty detailed list of guns in Walker's Div. Seems like some Ft. Pemberton weapons got no further than Yazoo City & vicinity. Absent an explicit statement about the Whitworth, we ought to be wary. John