My theory involving the Gem of Cyttorak
Hello, everybody!
I have read your discussion pertaining to whether or not Ultimate Juggernaut is a true mutant. I believe that Ultimate Juggernaut is NOT a mutant, but my reasoning for this may be a little far-fetched. If you look closely at the helmet of Ultimate Juggernaut, you will notice that the lens/goggles are a ruby red color, which I believe is the same color used for the Gem of Cyttorak. Personally, I believe that Ultimate Juggernaut received his powers magically from the gem like his 616 counterpart, and it is now incorporated as a part of his helmet to allow him to retain his magically-endowed abilities. Also, in the Marvel 616 universe, Weapon X was known for augmenting the abilities of those mutants under their "employment," and perhaps this tactic has been utilized by Weapon X in the Ultimate Universe as well. Ultimate Juggernaut may have exchanged his services for the ability to better control or even increase said abilities. Let me know what you think!