Nobody makes a 404 box, the Blackburn is a 416 box and its a poor substitute..Weisner made a 404 box at one time but no more...It is imparative to have the inside cuts in the sized .404 box ala the original Mauser..The original Mauser never failed, because of those cuts that only allowed side contact on the rim and shoulder, with the rest of the case and bullet free...Again Paul Mauser proved his worth....Remington has done the same with their box in the RUM series that are made on the 404 case and I have been told that you can use those boxes in a M-70 and come up with a functioning 404....

With a good tig welding gunsmith it is possiver to convert a Blackburn box or Sunny Hill box to a 404 that will function...