Dear Frank and Mike
I hate to quibble, but ..... the .303" rounds shown with the hollow nose are Mark 5 (Roman numeral "V") ball made by the Dominion Cartridge Company, Canada. They are not "Dum Dum". The actual .303' Dum Dum round featured a projectile with a rather small lead soft point and was called "the Dum Dum Mark II SPECIAL". It was introduced circa 1896-97 for the Indian Army and was obsolete in 1900. Perhaps some DDS's got to SA in the pouches of troops sent from India? The .303" Mk.5 ball rounds were introduced 11/1899 and ran afoul of an International convention on warfare; which probibited the use of "expanding" projectiles on humans. GB did not immediately ratify the agreement - but withdrew hollow nosed rifle ammunition from active service.
The .303" Mark II round shown with "6" in the headstamp was made by a so far unidentified Brit. Government Contractor; wheras the round with "1" was made by Birmingham Metals and Munitions Company - again on contract. All of the rounds shown have "C" in the headstamp; means Cordite propellent.
MkII .303" Cordite rounds of many and varied makers are widely found here in OZ and most would have come back from the ABW.
I have read the occasional source which claims Empire soldiers used "Dum Dum" (sic) ammunition in the ABW. One can never be certain at this remove and I sometimes wonder if commentators of the day saw ammunition packets MADE at Dum Dum and jumped to a conclusion.
To conclude, the Boers definitely did use soft nose 7mm and .303" ammunition of commercial manufacture.
Sorry this note went on for longer that I thought it would.
IL