In modern armies the G-4 is responsible for ensuring the units received the necessary ammunition.
Although it is very clear the Commissary Department was responsible for providing provisions who was responsible for ammunition?
If I am the battalion quartermaster and I need to replenish my ammunition who do I send the request to? Obviously through the brigade, but where to after that? The division's assistant commissary officer who is responsible for supplies? The division's assistant adjutant general? The division's assistant quartermaster general? And who do they submit the request to? Ward's Wellington's HQ as well as Haythornthwaite's The Armies of Wellington are a bit vague.
And if I am an artillery commander, whom do I submit the request for ammunition? One of the above? The army's chief-of-artillery?