Film sequence.

[Dave Mills]

From my Arty experience and not having worked on the medium 5.5 inch Howitzer Batteries and only beside them with the 105mm howitzer Batteries, I can say that the belt he is wearing is the Ballast charge rounds which is a blank .303 cartridge and is inserted in the back of the screw breach, the lanyard is pulled allowing the firing pin to strike the cartridge which then ignites the charge bag of propellant hurting the round down range with pin point accuracy. Go Arty.

As far as I can remember and having only worked beside the medium batteries all 5.5 inch rounds came with no fuse fitted,hence, the gun number inserting the appropriate fuse as ordered by the command post GPO.