OP
Texas Star
US Veteran
Just like in respect to the Little Big Horn, I would mistrust anyone who claims he knows why the battle turned out the way it did.
Both in case of the Little Bighorn and Isandhlwana, which interestingly happened just a few years apart, the fact that the losing side was completely wiped out (in Custer's case at least that part of the command on Last Stand Hill), and the winning side was not a "literate" culture in the Western sense, makes reconstructing both the sequence of events and any cause-and-effect conclusions quite tricky.
In both battles actual "schools of thought" developed over the last century as to what "went wrong", and competed with each other. In case of Isandhlewana, arguments have been made about the lack of alertness, deployment of troops, lack of scouting, the type of ammo, the ammo boxes and their closures, quartermaster rigidity in resupplying troops with ammo, etc.
None of them is probably wrong in the aspects they focused on, but I think it's impossible to prove that "this was THE reason".
I think that all of those reasons applied, but until I saw that program, I wasn't aware that many troops had ammo available, but had extraction problems and not enough light. They recreated low light conditions on a shooting range and showed how that affected accuracy as they fired Martini-Henry rifles in the gloom. Some of the darkness was from clouds of black powder smoke. Soldiers had trouble seeing some of the Zulu until too late.
A few years later, longer levers gave added extracting power, and I think the brass also improved. (And I suspect that .45-70 ammo used against Spain in 1898 was better made than that fired at Sitting Bull's warriors.)
And I don't think an alarm was sounded in time. The British were not standing-to, just going about their usual business in camp. Those gullies gave the Zulu opportunity to get in much closer than was expected. And I think the troops were astounded to be attacked by primitive "savages" who they probably thought would be cowed by their presence. They just thought their camp was too strong to tempt the enemy.
It was a combination of these factors that led to the Zulu victory.
The Boers showed in 1838 that alert European parties of reasonable size and using good tactics could defeat overwhelming numbers of Zulu. Apart from putting their trek wagons (like US covered wagons) in laager, their men rode out on their ponies and rode around the Zulu, firing into them. They 'd fire, withdraw and reload, and repeat. And added volleys from the wagons were also effective. Boer marksmanship has also been famous.
At Rorke's Drift, the Zulus had many rifles taken at Isandlwana and were shooting down into the fort. No one has mentioned that here.