IIRC from my reading of the actual history (The Washing of the Spears) decades ago, besides being caught in a horrible position out in the open, the quartermaster aspect of the problem was that the British ammunition was very stoutly crated in screwed together wooden boxes, and they simply couldn’t unscrew the crates quickly enough to get at enough ammunition. No one had DeWalt electric screwdrivers back then.
Isandlwana:
“In the next few minutes, every man who was fated to survive the coming massacre would fly the battlefield. Destiny, luck and horsemanship would decide who would live and who would die. Yet, as the last of the lucky riders spurred away down the ‘Fugitives’ Trail’, several hundred men on foot were still alive and fighting hard. With few notable exceptions, historians have done these men a disservice. In the telling of their tale, the scholars have killed them off easily and precipitately in front of the camp. The clear-cut hopelessness of the situation, the overpowering odds they faced, the renowned martial skill and ferocity of their opponents – all the first glance factors – have driven the historians to their inevitable conclusion: whole companies were slaughtered in a few short seconds. Yet, in truth, it is clear that the Battle of Isandlwana raged long and hard after the flight of the lucky ones.
No white man who fought in the final phase of the battle would live to tell the tale of the desperate stand made by these few hundred stalwarts. Clustered around their officers and sergeants, the men of the 24th Regiment were the backbone of a heroic resistance. Through a succession of largely defective interpretations of the evidence, the story of the last stand of the 24th has almost been lost to history but, for those with the eyes to see, it survives yet. By the application of a little military common sense it can be reasonably accurately reconstructed. When the Zulu main bodies reached the tents, the great majority of the 600 redcoats in the field that day were still alive. They were not scattered over the open veldt before the camp, as many would have us believe. They were formed in close order, they were resolute and they were skilfully led. They were grim, frightened, and knew that they were doomed to die. Above all else though, with the stubborn arrogance that has typified the British infantry over the centuries, they were determined to sell their lives dearly. It was to be a fight to the finish with no quarter asked or given, and these men would take some killing; a lesser foe might not have achieved it. This is the story of those men and of the brave warriors who killed them. By any standard it is a tale of extraordinary high drama.
This is a story of Briton and Zulu, two peoples who fought each other with such remarkable courage that, even before the last shots of 1879 had been fired, it had forged a mutual respect so profound that it would blossom in next to no time into a strong friendship, a relationship that survives to this day and continues to flourish. With the sweeping away of apartheid and the normalisation of Anglo–South African relations, members of the modern regiment are now frequent visitors to Zululand. In our train have come more and more tourists, keen to experience the renowned beauty of the countryside and to pay homage on the great battlefields. Whatever small part we in the Royal Regiment of Wales have been able to play in further cementing the friendship of the British and Zulu peoples we are inordinately proud of, for the man lucky enough to call a Zulu his friend will come to know something of the nobility and majesty of old Africa.”
https://www.scribd.com/book/444093997/How-Can-Man-Die-Better-The-Secrets-of-Isandlwana-Revealed