Call of Duty: Modern Warfare 4 Apex Attachments Explained: Every Confirmed Weapon Mod

Call of Duty: Modern Warfare 4 launched October 23 on PlayStation 5, Xbox Series X|S, PC and Nintendo Switch 2, and one of the biggest changes Infinity Ward made to the moment-to-moment gunplay is a new weapon-mod tier called Apex Attachments. Unlike a normal scope, grip or barrel, an Apex Attachment doesn't just nudge a stat bar — it changes how the weapon fundamentally works, turning an assault rifle into a grenade launcher or an SMG into a through-wall tracking tool.

Here's how Gunsmith and Apex Attachments actually work, which weapons have confirmed mods right now, and the one attachment the community is already arguing about.

1. How Gunsmith Attachments Work

Modern Warfare 4's Gunsmith splits standard weapon customization into nine attachment categories: Optics, Lasers, Barrels, Muzzles, Underbarrels, Stocks, Rear Grips, Ammunition and Magazines. A weapon build can equip up to five of these standard attachments at once, and each individual attachment only needs to be unlocked one time — once you've earned it on any weapon that can use it, it's available across your whole arsenal.

If a weapon level-up would hand you an attachment you've already unlocked elsewhere, the game automatically skips it and gives you a Bonus Level Up instead, so progress never feels wasted.

2. What Makes Apex Attachments Different

Apex Attachments sit in their own slot entirely separate from the five standard Gunsmith picks, so equipping one never costs you an optic or a grip. Rather than small handling or recoil adjustments, each Apex Attachment is built to meaningfully change what the weapon does in a fight — swapping fire modes, changing ammo types, or bolting on an entirely new function.

Infinity Ward has confirmed 28 Apex Attachments across the full weapon roster. Most supported weapons get one unique Apex Attachment, though several — including the Hyeon Burst and the Kastov 762 — ship with two different options to choose between.

3. How to Unlock an Apex Attachment

An Apex Attachment is awarded as the final reward for leveling a supported weapon all the way to its max rank, and that XP can come from either Multiplayer or DMZ matches since both modes count toward weapon progression. Not every weapon in the game gets one: Default Loadout-only weapons like the Axion and the Sang 9mm don't have Apex access, and neither does the PILA launcher or the Combat Knife.

4. Every Confirmed Apex Attachment

This is the full list of Apex Attachments Infinity Ward has detailed so far, organized by weapon. The WZ.55 Striga's Apex Attachment is still classified and hasn't been shown publicly.

Assault Rifles

• Han 86 → Han X20 Skybreaker: a targeting optic paired with a launcher that fires a 20mm airburst shell, effective at flushing players out of cover.
• M4 → M4 Hurricane: a top-loading, high-capacity conversion chambered in 5.7x28mm.
• Hyeon Burst → Hyeon Auto (full-auto fire) or Hyeon Hyperburst (a three-round burst followed by a slower automatic string).
• Kastov 762 → Kastov 545 (converts to 5.45x39mm for smoother handling) or Kastov ARC (a disruption barrel with an integrated optic that emits an RF pulse affecting infantry, electronics and vehicles).
• Patriot XMR → Volt: an underbarrel launcher that fires non-lethal electric darts.
• Axion → Crusader: a compact, high-mobility conversion with a saw stock (Default Loadout only).

SMGs

• ISO Nightshade → Trace: equips RFID-tagged ammunition that marks hit targets and feeds their movement to your optic, at the cost of reduced bullet velocity and penetration.
• PPSh-41 → Ember: an underbarrel attachment that fires incendiary rounds for area denial.
• X-58 Nyx → Void: a quieter, subsonic build that hides kill skulls and reduces directional hit indicators.
• Sang 9mm → Sang 9B&12: an underbarrel single-shot 12-gauge chamber (Default Loadout only).

LMGs, Marksman and Sniper Rifles

• Rezi 12 → Enforcer: pump-action cycling with side-mounted explosive slugs.
• FiNN LMG → Adverse: an unthrottled fire rate that can overheat the weapon.
• Type 73 → Assault: a top-mounted magazine loaded with explosive rounds.
• MAR-9 → Auto: converts the marksman rifle to fully automatic fire.
• Oris 8.6 → Razor: a receiver-mounted blade module with rapidly deployable kunai.
• KG-7 Vulcan → KG-9 Drillcharge: side-mounted charges that drill into surfaces before detonating.
• Signal .50 → Inferno: incendiary rounds that boost damage against vehicles and killstreaks.

Pistols

• Karit P68 → Commando: improved melee damage and lunge range.
• .50 GS → GS Magna: fully automatic fire, traded for accuracy.

5. The Attachment Everyone's Talking About: ISO Trace

Of everything on this list, the ISO Nightshade's Trace attachment has drawn the most attention. Once unlocked, it loads the SMG with RFID-tagged ammunition — hit an enemy and their position starts feeding to your optic, letting you track their movement through walls for a short window. Community coverage has nicknamed it a built-in "wallhack," though Activision's own framing presents it as an intentional, balanced multiplayer system rather than an exploit, offset by the attachment's reduced bullet velocity and penetration. Expect this one to be a target for early balance patches once ranked and competitive playlists settle in.

6. Apex Attachments Carry Over Into DMZ

Apex Attachments aren't locked to Multiplayer. Activision's own DMZ breakdown confirms that DMZ's extraction mode is built on the same movement, gunplay and Ballistic Authority gunplay system that powers Multiplayer, so any Apex Attachment you've unlocked on a weapon applies whether you're dropping into a 6v6 map or extracting from the Hajin exclusion zone. Since weapon XP earned in either mode counts toward the same max level, grinding a gun in DMZ's slower, higher-stakes matches is just as valid a path to an Apex unlock as playing Multiplayer.

7. Quick Tips for Unlocking Apex Attachments Faster

• Pick one weapon and stick with it — Apex unlocks are tied to a single weapon reaching max level, so spreading XP across multiple guns slows every unlock down.
• Both Multiplayer and DMZ matches count toward weapon level, so use whichever mode you're already playing instead of grinding a mode you don't enjoy.
• Check the Gunsmith screen's level counter before a match — it shows exactly how many levels stand between your current build and the Apex slot unlocking.
• Don't skip Default Loadout weapons expecting an Apex payoff — the Axion, Sang 9mm, PILA and Combat Knife don't have one to earn.

Apex Attachments are one of the clearer signs that Infinity Ward wants Modern Warfare 4's gunplay to stay interesting well past launch week — a top-tier unlock worth chasing on every weapon in the Gunsmith, not just a cosmetic finish line. For everything else that shipped alongside it, check out Kill Block, the new day-one multiplayer mode, or the full rundown of launch editions and Warzone plans.

Quick recap: Apex Attachments are a separate, powerful mod tier unlocked by maxing out a weapon's level in Multiplayer or DMZ, they don't use a standard Gunsmith slot, and 28 are confirmed across the roster so far — with the ISO Nightshade's through-wall Trace attachment already the most talked-about of the bunch.

Official Resources:

• Call of Duty: Modern Warfare 4 official site
• Call of Duty: official Gunsmith and Apex Attachments guide
• PlayStation Blog: Modern Warfare 4 launch overview

For more on this year's biggest shooter, browse the full walkthroughs.net guide archive.