Unfortunately I cant find much reliable estimates of RN ammunition expenditure for each kill. some sources suggest or estimate about 1000 rounds per kill, but that seems pretty optimistic. From the look of it, I think we are going to have to look at random or typical enagements to get a representative sample....where the ammunition expenditure is known, and the number of kills is also known. Anyone got any examples like that?
I gave a couple of examples earlier, but it becomes a pretty huge task. I looked through the USN AA summary linked earlier, and it is stating a lot more AA kills than I'm aware of. Since it was published in Oct 1945, it must have been based on wartime claims, not post war verified AA kills.
Here's a summary of RN AA technology:
The Gunnery Pocket Book - Part 4