These were 4"/27
(10.2 cm) guns converted to take the same cartridge case ammunition
as used for the 4"/40 (10.2 cm) QF guns.
Between 20 and 27 guns were converted from 4"/27 (10.2 cm) BL Marks IIIA,
IV, V and VI. These were redesignated as QFC I/IIIA, QFC I/IV, QFC
I/V and QFC I/VI, although in gun lists they were always referred to only
as 4" (10.2 cm) QFC guns. Actual bore length as converted was 27.78
These guns were converted by giving
them either new 'A' tubes or short bore and chamber liners, which resulted
in them having the same chamber size as the 4"/40 (10.2 cm) QF guns.
These converted QF guns replaced BL guns on Inflexible and the gunboat
Lapwing. During World War I, a few were still in service on DAMS
and three were used by Belgian gunboats on Lake Tanganyika in Africa.