Nickjc ... too Hi Tech for me!
It looks like you are doing fine and destined to become the KCA: "Bandoleer Balladeer".
I bet you can connect two of those bandoleers together. A blue one with a khaki would look nice! ;D
(In all honesty, this complicated bandoleer & buckle-device looks like the kind of thing that fell by the wayside. Possibly, made redundant by the handy and disposable light cloth & safety-pin bandoleers ammo came 'packed in' from the arsenals)?
The ubiquitous (cheap & disposable) cloth bandoleers seem to have been around from Krag to M-14.