its probably a 7.63 mm as that was common for hunters and millitary personell to buy one if they needed on, and he chased away a group of native warriors with that one time, as Capstick wrote about it, and those ten rounds would probably be very handy in case of a ratrap.

China bought a million of mauser pistols and Astra copied it , it was a pistol that was better than a singleshot pistol to have and who knows, if i were in Africa at that time, would feel more certain if i didnt have a psitol that could be turned into a carbine easily and have several ten rounds clips handy if something unexpexted would happend?