Brass for the .43 Mauser is easily found in the USA - from Track of the Wolf for one outfit and others. I suspect, same for .450 BPE or Nitro brass.

What the curent laws are in Sweden, I don't know, however - either ctg. can be loaded to be very useful on any game you have there.

As to Africa, there are much better choices than black powder era ctgs.

As to the .43 Mauser, you will have to establish what the groove diameter is - if it is as in the 71/76 or ealier models, ie: between 1871 and 1876 Mauser and has a .457" groove diameter, it wil not be very accurate as the chamber will only allow a .446" bullet to be loaded and chambered in the rifle. If it has a .446" groove diameter such as the Model 71/84, then it will be just fine.
I have a 90% Model 71/76 with the .457" groove diamter and got over the bullet diameter problem by re-chambering to .450 Alaskan. I only use black powder-type loads.
The .450 Alaskan case (blown out .348Win case) holds a little more powder than the factory Mauser case and I am able to duplicate the .45 2.6" Sharps with it- 1,400fps with 500gr. bullets - black powder or smokeless loads. This is more than enough power for moose, elk, grizzly, whatever.

Factory .43 Mauser have a 370gr. bullet at about 1,380fps using 77gr. black powder. It is very similar in effectiveness to the .45/70 round of the USA.

Here's the round I re-chambered my .43 Mauser to, to allow for proper sized bullets and for ease of obtaiing cases. When I aquired the .43 Mauser M71/76, brass was hard to find, not now. A simple re-cutting the neck area of the chamber to .483" or .484" will allow chambering the proper bullet size. The reamer, called a 'chucking' reamer costs approx. $25.00 and is available from Pacific Tool and Gauge.

The ctg. on the left is the .450 Alaskan.

The case on the right is what I call the .458 Alaskan, rim turned off and cut (rebated) to .532" for use in a modern bolt actioned rifle.