Best Napalm Burst Augments in BO7 Zombies

Napalm Burst is one of the weaker ammo mods on its own, but the right augments change that completely. Firebomb turns a 2-kill activation into a 50-kill chain. Here is what to run, what to skip, and when the mod actually earns its slot in a real build.

We tested every Major and Minor ourselves in live runs, including Big Game specifically against the Zursa on Ashes of the Damned. The results do not match what most guides recommend.

The Best Napalm Burst Augment Build

Firebomb is why the build works. In our own runs we chained a single activation to 50 eliminations. Each enemy that dies from the burn explodes, spreading fire to the next zombie, which then dies and explodes again. Extension keeps each burn tick going longer, giving the chain time to build. Incendiary adds a second spread chance on every damage tick on top of Firebomb’s explosions.

What Napalm Burst Actually Does

The official description reads: “Bullets deal Fire damage. Each bullet has a chance to apply a burn effect on Normal and Special Enemies, dealing damage over time.” Normal and Special zombies only. Elite enemies are not affected unless you run Big Game.

Without augments the mod is genuinely weak. A standard activation killed 1 to 3 zombies in our testing, which puts it behind most other mods at the same 500 Salvage price per weapon. You are spending real resources on something that does not pay off until the augments come online.

Napalm Burst is also worth having on any build that runs Elemental Pop, because Elemental Pop can trigger augments from mods you have not equipped. Setting the right augments before you leave Napalm Burst unequipped still benefits those random triggers.

How to Unlock Every Napalm Burst Augment

The research diagram opens after just 3 total augments unlocked anywhere in your account, which is the lowest requirement of any ammo mod. Cryo Freeze needs 6, Fire Works needs 9, Shadow Rift needs 18. You will likely cross the Napalm Burst threshold before you ever actively target it. Player Level 35 is also required.

The grid has nine nodes across three rows, with one node researching at a time. One player-logged dataset puts the cumulative XP at 525,000 to finish all nine, with Extra Slot as the final node at roughly 135,000 XP above the previous unlock. The tester flagged this as an estimate with low confidence, so treat it as a rough guide rather than a fixed number.

For this specific build you need to finish the full grid, because running two Minors requires Extra Slot, which is the last thing that unlocks. If you only want Firebomb with a single Minor, you can stop earlier once Extension is available and redirect research elsewhere while you wait.

All Major Augments for Napalm Burst Ranked

Firebomb (S) is the only Major that makes the mod competitive. The description: “Burned enemies explode on death, spreading the fire to nearby enemies.” In a tight horde each death triggers the next explosion, and that chain kept going up to 50 kills in our runs. The community effect matches too: one Reddit tester reported 40-plus kills from one activation using Firebomb with the spread Minors.

Petroleum (A) drops a fire pool on the ground on activation, like a Molotov. In our runs we pulled about 8 kills per pool, with the fire lasting around 8 seconds. That is real value if you hold a fixed spot.

Thermite (B) increases burn effect damage. We tested it directly: Thermite with Extension and Incendiary produced a maximum of 4 to 5 kills per activation in a dense horde. The damage number goes up, but without the chain mechanic you are just killing slightly more zombies per trigger rather than dozens.

Big Game (C) makes Napalm Burst burn Elite enemies more frequently. The obvious use case is the Zursa on Ashes of the Damned, which has fire as its elemental weakness. In our testing, we specifically targeted the Zursa with Big Game equipped and could not get a single activation.

Even if Big Game does trigger, the damage from a single burn on one Elite does not justify passing on Firebomb’s horde clear. Firebomb deals with the crowd surrounding the boss while the base burn ticks away.

All Minor Augments for Napalm Burst Ranked

Extension (S) increases burn duration. More time burning means more death explosions from Firebomb, which is directly more chain length. This is the first Minor you want and the one you run alone until Extra Slot opens.

Incendiary (A) adds a small chance for each damage tick to spread to a nearby enemy. The official description uses the word “small,” and it reads accurately: the activation rate is low, and it does not spread reliably on its own. Combined with Firebomb’s explosion mechanic it adds one more way the chain extends. Not strong enough to run solo, but worth taking as the second Minor once you have Extra Slot.

Contact Burn (B) increases the damage on the initial burn hit. Functional, but it helps the first second of activation rather than the sustained chain. Extension beats it for supporting Firebomb, and the Contact Burn plus Petroleum pairing needs its own post-fix retest before recommending it here.

Backdraft (C) increases the activation radius. More enemies in range when it activates should mean more chances to start a chain. In practice we did not feel any difference in chain length or activation frequency compared to running Extension and Incendiary. Skip it.

When to Run a Different Ammo Mod

Honestly, Fire Works and Shatter Blast are more consistent choices across more maps and round ranges. Napalm Burst earns its slot in two specific situations: when you are on Ashes of the Damned and specifically targeting the Zursa, and when you are building around Elemental Pop and want the passive triggers from Napalm Burst to have the right augments set.

One open question we could not resolve: whether Kowakujo’s Scorched Zombies resist fire and prefer Cryo Freeze. If you notice Napalm Burst underperforming on that map, swap to Cryo Freeze or Brain Rot and see if the kill rate changes.

Frequently Asked Questions