CZ550 mag length

[425SCHADE]

CZ 550 magnum experts,

Chasing some confirmation and advice on the magazine and feed rail specs on the CZ 550 American Magnum "standard" model for the various chambering's.
I wish to use the 550 as a platform for my wildcat cartridge based around a slightly improved .416 Rem Mag with COAL of 3.600" and have found a new rifle currently in .458WM.
Does the .458 have a full length mag? Will the rail opening be too wide?

 

[IvW]

Yes full length mag.
No rail should be fine exact same size as 458 WM

 

[425SCHADE]

Thanks IvW,