Because of the original balistics of the 404 it is assumed that 2100 to 2300 FPS is all it will do..Check the case capacity and you will be awakened...
I can get 2653 FPS with a 400 gr. bullet in a 26 inch 404 Jefferys with 95 grs of IMR-4831..I have chronographed this load and loaded one case 14 times and it was still good..I sent these loads to Norkfork Bullets for testing and they got 2550 plus something in a 24" test barrel and stated they were within safe pressure limits..I got this load from Rifle magazine some years ago, and have been using it ever since.. I load my 404 Jefferys at 2400 FPS for hunting DG, as that is the magic velocity IMO..
The .416 on the other hand can be safely pumped to 2700 FPS with a 400 gr. bullet but again eveyone loads it to 2400 FPS as again that is the magic potion..and I agree that it is..
The bottom line is you can build a 404 on a std. action and the .416 Rigby must be on a full size magnum action and that makes the Rigby a larger rifle..however my 404 is built on a full size magnum action.
Its a push no matter what you do..Take your pick..I picked the 404 for no particular reasons.
