Mo' Money is an Epic gun perk in Call of Duty: Infinite Warfare exclusive to the Volk - Corruption variant. Extra XP is rewarded to the player for every kill they earn using this weapon, and it is the only weapon that rewards players with the "Mo' Money" Medal during matches.

Does Mo Money affect weapon XP?

Mo' Money currently only gives players additional XP for kills, which does nothing to help players trying to win a match.

What gives you weapon XP in Modern Warfare?

Each weapon has a different sequence for progression. You'll unlock different things at different levels. You will also unlock cosmetics as you level up a weapon. Weapon XP only comes from kills.