There were several marks of ordnance (the barrel and breach assembly) and several marks of carriage of both versions, the carriage included the recoil system, laying arrangements, fuze setting and loading machinery.
There were several six marks of ordnance (the barrel and breach assembly) and a few marks of carriage of both versions, some using letter suffixes. The carriage included the recoil system, laying arrangements, fuze setting and loading machinery.