One of the Act 1 challenges that keeps repeating in different forms in Call of Duty Modern Warfare 3 Zombies requires you to gain access to a certain Ammo Mod and then use it in multiple different ways on poor Zombies to learn how they affect them.
Thankfully, all Ammo Mods in the Zombies mode can be obtained similarly, which makes it quite easy for you to know where to look for them. Of course, this also means you need to be lucky to get the Ammo Mod that you need, as there are five unique mods in total.
How To Get Ammo Mods In MW3 Zombies
There are three major ways to obtain Ammo Mods in the game. While two of them are always available, the third method is a one-time-use method that you cannot repeat later in the game.
Loot Aether Caches & Reward Rifts
If you want to find ammo mods by exploring the world, they can only be obtained from Aether Caches or Reward Rifts. As you may already know, completing each contract in Zombies will open a Reward Rift that comes with valuable items, which may include an ammo mod as well.
On the other hand, you have Aether Caches, which are lootable crates with purple crystals on them. The best location to find these caches is Infested Strongholds. These buildings are scattered around the map, and you need to get inside and shoot down some yellow rotten cores on the walls and floors to cleanse the building. Based on the scale of the building, you may find up to three Aether Caches, and if you are lucky enough, you may also get a few ammo mods as well.
Craft Ammo Mods
Crafting Ammo Mods will allow you to equip them before dropping them into Urzikstan, but it will first require you to find the dedicated schematics of that mod. The schematics can be found almost anywhere, as you just need to explore and loot crates and chests.
However, finding a schematic is not enough, as you need to extract it to be able to craft the corresponding ammo mod, which makes things a bit more complicated.
Complete Objectives (Single Use)
There are some objectives that will reward you with certain ammo mods upon completion. For example, completing the Take Up Arms objective in Act 1 Tier 1 will give you a Cryo Freeze ammo mod for free. In the same Act, you can also complete the Blasted objective to receive the Napalm Burst ammo mod.
These rewards are one-time-use, which means if you lose the ammo mod afterward, you cannot complete the objective again and get back the rewards.
What Do Ammo Mods Do?
This section of the guide will take a quick look at each Ammo Mod and what they are capable of. Also, we will let you know which weapons are best for certain ammo mods to tackle the objectives faster and easier.
Cryo Freeze Ammo Mod
The first Ammo Mod objective in Act 1 will require you to freeze a number of Zombies using Cryo Freeze and also slow down some Hellhounds. It is quite important what weapon you equip the mod with. We strongly suggest you equip Cryo Freeze with SMGs, Assault Rifles, or Pistols. Simply, any weapon that won’t kill Zombies or Hellhounds with a single shot is good to go with Cryo Freeze.
The reason for that is the fact that when you are required to slow down Hellhounds, you need to shoot at them without killing them, so the Cryo Freeze effect is applied to the Hellhound and makes it move slower. However, all Ammo Mods have a random effectiveness. This means not all your shots will be infused by Cryo Freeze. So, if you want to complete this objective quickly, stop shooting at the heads, and just try to kill Zombies with as many shots as possible so that you can finally get Cryo Freeze applied to them in one of your shots.
Brain Rot Ammo Mod
This mod will turn a Zombie into an ally, which makes them attack other Zombies rather than you, and then explode when the mod’s effect has expired. Similar to the Cryo Freeze mod, you need to avoid insta-killing a Zombie to be able to apply the mod to them.
Shatter Blast Ammo Mod
As the name implies, this mod makes Zombies explode, dealing AOE damage to other zombies or enemies surrounding them. This is quite an effective mod for crowd control, especially when you are in the exfil zone and waiting for the chopper to arrive.
Similar to Cryo Freeze, the Shatter Blast’s objective is also accessible in Act 1, which requires you to apply the effect to a certain number of Zombies.
Napalm Burst Ammo Mod
Unlike Shatter Blast which causes an explosion, the Napalm Burst mod will make Zombies and other types of enemies burn from the inside. So, your bullets will now deal burn damage in addition to their normal damage, and the duration of the burning effect will be increased as your mod’s tier goes higher.
Dead Wire Ammo Mod
If you want Zombies to leave a magnetic bolt after their death, Dead Wire is the best ammo mod to use. Not only does it slightly slow zombies down, but it also applies AOE damage to the surrounding enemies, which makes it quite a useful mod to equip with every weapon.