I usually have at least three airlines to get to Africa but one main international carrier. The main routes we use are served by Delta and Qatar. For most itineraries it is not "end to end" as we usually have a domestic carrier in Africa to get to the final destination and in my case AA to get going. Regardless of the route and regardless of what people say online you do not want to interline from one airline to another with rifles. There are many issues that can come up ie the second airline wanting to inspect and asking for more or nonexistent paperwork.
I am not trying to be a know it all but I see the issues and have lived them. Someone buys their ticket on their phone, then has a big mess up with rifles, and they instantly become the ambassador of "it's not worth it use a camp gun".