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They are also one of the items that can be upgraded with Aetherium Crystals to enhance the power of them, with five tiers of upgrades being available.
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Unlike the prior games, the weapon does not need to be Pack-a-Punch'ed to be equipped with an Ammo Mod. Ammo Mods can be added to any standard weapon either via the Pack-a-Punch Machine for 2,000 Essence or via finding an Ammo Mod pickup earnt from a source, such as a World Event in Outbreak.
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The Ammo Mod upgrade is a system introduced in Call of Duty: Black Ops Cold War, functioning as an evolution of the Upgrade Modules from Call of Duty: Black Ops III and the Alternate Ammo Types from Call of Duty: Black Ops 4.
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