From my experience I have found the aluminium checks I make are as good and sometimes better than the copper (factory) checks up to about 1900fps. As has been said the 44 mag checks work for the 404 but I had a second stem made with a smaller nose for the 424 bullet and it has proved to be a cheap way to "double up" on the freechex checkmaker. In the same way my 7mm maker also makes checks for my 6.5 with a smaller nosed stem and again for the 303 maker that will also make them for the 30 cal. Having 3 freechex tools I can now make checks for 6 cartridges.
This is the 44 mag freechex tool with the 44 cal stem havinng the case on top and the smaller nosed stem for the 424 bullet