Over my 4 safaris in Cameroon, I have hunted with 2 different outfitters. On all 4 hunts I had to send my passport to Paris and or Brussels to some agent who took my passport to the embassy and got me a visa. Once he secured the visa he would send my passport back to me. This is not a difficult process, but it always gave me anxiety to send my passport away ahead of an upcoming hunt. If I recall correctly it cost around 300 for the FedEx charge, then the guy getting the visa and other paperwork charged around 600 for his services.
As a part of this process I had to send my gun details, form 4457, fill out other forms, then email those. When you arrive in Douala, it is fairly simple, however, it will take quite a while to get through the airport, it can take 1 to 1 1/2 hours to get your gun processed in Douala. I would have no idea why other than it's 'African time' and we all know what that means.
Another quick note about the airport in Douala, there will be a checkpoint once you land to see your yellow fever card, another one to ask your age and ask what you do for a living, another one where you fill out a health form, then you get to customs. Again, it is not difficult, but it takes a lot of time, it is hot as hades, there is NO AC, so you stand in line and sweat, lol
If you are going to Cameroon, it is imperative to have someone on the ground to get you through the airport, on my 2nd trip through Douala the guy I paid 600.00 to help get me through the airport did not show up, I'll save that story for another time, but trust me, it was anxiety overload.