I see the 404 as being quoted as 2100 top 2300 FPS rifle on many of these posts, it has become an accepted fact when, in fact, nothing could be further from the truth..The 404 has simply been loaded down over the years due to the old cordite syndrome...Same for the .416 Rigby and to a lesser extent for the .416 Rem..All these guns can be safely loaded to more velocity.
The 404 has almost the same powder capacity as the 416 Rigby. 95 grs. of IMR-4831 in my old Jefferys bolt gun got me 2653 FPS in that 27 inch barrel..I have North Forks Mike Brady test these loads in his lab and his shorter test barrel got 2550 plus FPS at reasonalble but max pressure. I have hunted Cape Buff with this load many times and its devistating on the black bulls, they shudder at impact..I have friends that shoot the 416 Rigby at almost claimed 2800 FPS and that is their hunting load.
Somewhere in time some "expert" claimed the best velocity to kill big dangerous game with was 2400 FPS, and that has been printed and reprinted many times....I don't believe that and believe the faster you push a good properly constructed bullet the better it will kill or at least the more damage it will do. That only makes since.
That said, I do load 404 Jefferies, .416 Rem, and 416 Rigby calibers at 2400 FPS with a 400 gr. bullet, or even a tad less simply because recoil becomes a factor at those higher velocities, and at 2300 to 2400 FPS a 40 caliber kills well enough to suit me on any animal, and therein our "expert" was correct in that since....