MauserRifle:
If I could buy a classic Mauser actioned sporter in .404 Jeffery, I would take this over the .416's or .458s out there now. The cartridge shape and low pressures, I feel, are a plus. Hot weather and pressures are less likely to be a problem. The long slope to the shoulder eases feed. It is plenty powerful for anything you are likely to hunt (maybe not elephant?).
As I said before, I have an FN Sporter on a standard length '98 action in .375 H&H. There are cuts for ejection and the magazine is opened longer. All of this is factory. This is an older model from, I assume, the 1950'. It has both the classic mauser 3 position wing safety. It also has a side slide safety that seems to have been included to allow for lower scope mounting. It is drilled and tapped (thru the ornate FN emblem on the forward ring) though only irons were on the rifle when I bought it. I was told it was a "guide or game scout" rifle. In some reading over the past few years, it seems that Tanzania or Zambia equiped their game rangers / scouts with .404s contracted to FN. I don't know where my rifle has been, but, even though in nice shape, it has seen some carrying and hunting.
Good luck with the project or hunt for the purchase. I would be interested in what you end up with.