Edit: Just realized I have a 375 HH mag box/ejector/bolt stop off another project. Maybe a 458 with a longer box?
The longer box would be a good thing, allowing the seating of long bullets longer. As to a 22" vs a 24": some velocity is lost, obviously, but how much would depend on how it would be loaded, if handloaded. I've owned a 77 Ruger in .458 with a 22", but the action was also shorter making it kinda compact for a .458. The CZ 550 in .458 I owned for a few years was taken on a moose hunt which meant some trekking through alder patches, but I didn't really notice the extra 3-inches of barrel. I doubt that the extra 2-inches of a 24" tube would ruin your day. My current Ruger #1 has a 24" but without a magazine as a single shot it is quite compact, though as heavy as the CZ 550. That extra weight is in the barrel that helps tame recoil jump.
Bob
www.bigbores.ca
