In early July of 1862, four 24 pdr iron Siege guns (two of which were rifled) were sent from Briarfield Arsenal in Columbus, Miss. to Vicksburg. In a separate shipment, 120 - 24 pdr Read balls and 80 - 24 pdr Read shells were sent from Columbus to Vicksburg. The ordnance at Grenada and Columbus at the time was the shot and shell removed from Memphis (Brooks & Gaynor, Quinby & Robinson, M & C R. R., Street, Hungerford & Jackson, to name the major suppliers, as well as C. B. Churchill which had contracts with the Memphis Arsenal) There was one 24 pdr rifled 24 pdr in the defenses at Snyder's Bluff, above Vicksburg. Several of the guns in the defenses at Snyder's Bluff, Drumgould's Bluff, Hayne's Bluff, Grenada and Fort Pemberton, were shifted back and forth according to whether the Yazoo River was up or down, and as the need arose due to pressure from the enemy.