Marvel Champions Codex
RulingRules Reference 1.7
Can Gauntlet Gun’s resource ability be triggered when paying a cost other than for a War Machine event in order to…
Question
Can Gauntlet Gun’s resource ability be triggered when paying a cost other than for a War Machine event in order to place 1 ammo counter on War Machine?
Answer
No, Gaunlet Gun’s resource ability can only be triggered when paying for a War Machine event.
— Rules Reference 1.7