The problem that I have with Major Dartnell's return is that it records the rifles obtained by the Natal Government during 1878 and 1879 without indicating exactly when. It is thus probable that some of these arrived following the cessation of hostilities.
However, over this period only 50 Martini Henry Carbines were received as opposed to 2040 Swinburn Henry Carbines. In view of their limited number and in the absence of specific information covering their issue, I suspect it likely that the Martini Henry Carbines were merely issued along with the Swinburn Henry Carbines to the Natal Volunteer Mounted Units. If so, they would have both seen active service.
Unfortunately, contemporary accounts make it very obvious that those who carried these arms did not appreciate their finer points. A Martini remained a Martini irrespective of whether it was actually a Martini Henry or the similar looking Swinburn Henry!
In view of the numbers involved I thus very strongly suspect that Lt. Stafford in all probability carried a Swinburn Henry at Isandlwana. This view is possibly supported by Lt. H. Davies of the Edendale Contingent who recorded that his carbine was equipped with a 9 inch bayonet - a characteristic of the Swinburn Carbine and not the Martini.