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Manchester Ordnance & Rifle Co of 51, Sackville Street, Manchester
Established by Joseph Whitworth. Guns (rifles and cannon) made by Whitworth in the late 1850s and early 1860s were variously marked either with the name Whitworth or Manchester Ordnance & Rifle Co  The same source comments that the rifles were almost certainly constructed by J. W. Edge of Manchester, using Brazier locks and metal components from Preston and Palmer. Presumably the highly advanced barrels and the required precisely-made ammunition were made by Whitworth.
1863 Slater's Directory of Manchester and Salford, 1863 lists Joseph Whitworth and Co as 'Manufacturers of Whitworth patent rifles, cannon and ammunition', and also includes the Whitworth Ordnance Company of 44 Chorlton Street as manufacturers of Whitworth patent breech-loading rifled cannon and ammunition.
It is not possible from the 1863 Slater’s directory to pinpoint No. 51 Sackville Street. However, Goad's Insurance Plans Map No. 50, dated 1893 (updated 1899) shows No. 51 as one of a group of industrial buildings at the southern corner of a block bounded by Sackville Street, Canal Street, Chorlton Street and Whitworth Street. These buildings were built on the site of a former canal wharf, while the northern part of this block formerly accommodated Whitworth’s Chorlton Street Works. The site is now home to a college building and a garden.