Yup. They couldn't get their ammo boxes open apparently. The battle depicted in Zulu occurs at Roark's end, one or two days after Isandlwana. The big surprise for the Brits is that the Zulus have guns (which they captured at Isandlwana) but couldn't use very well. So, yes, historically speaking, the Zulus could massacre.
What I was trying to say is that ZULU (or perhaps my interpretation of its ending) suggested that there are different kinds of wars. Just as in the animal kingdom the fight does not go on to the death, so human wars might be waged to establish boundaries, but not to obliterate.
The first time I saw Zulu was the first time this idea occurred to me -- so maybe that's why I think of it as an anti-obliterating-war kind of movie.
Joanna B.