Gunsmith and Attachments

4:34 Gunsmith in Call of Duty: Modern Warfare 4 builds a weapon from five attachments plus one Apex attachment, which does not use a slot, as GameSpot's loadout guide and Activision's Oct 19, 2026 launch blog describe. Attachments unlock by leveling each weapon, and they are shared: once one is unlocked, every weapon that takes it can use it. The game launched with more than 500 attachments and 28 Apex attachments, and a built-in optimizer called Gunny suggests builds from what you own. This page covers the slots, Apex attachments, weapon leveling, Weapon Prestige and blueprints; the weapons themselves are on Weapons, and finished builds on Best Loadouts.

Quick facts

Sources: Call of Duty, Oct 19, 2026, Call of Duty, Aug 21, 2026, GameSpot, Call of Duty progression blog.

Attachment slots

Activision's Oct 19 blog lists these attachment types:

• Optics: Mini Reflex, Reflex, Holo, 4x Scope, Marksman Scope and Rifle Scope, with thermal and plain versions of the Holo, 4x, Marksman and Rifle Scope (progression blog).
• Lasers, Barrels, Muzzles, Underbarrels, Stocks, Rear Grips, Ammunition and Magazines on most guns.
• Weapon-specific slots: Comb, Bolt and Guard (all three on the Rezi 12), Trigger Action (the MAR-9 and some pistols), Cylinder (the Mojave .357) and Fire Mods, which replace the Ammunition and Rear Grip slots on the PPSh-41.

4:35 Gunsmith rates a build on Damage, Range, Accuracy, Mobility and Handling, with a Details menu for deeper numbers, and Infinity Ward's launch patch notes say Advanced Weapon Stats are in Gunsmith at launch. Launchers and the FSS Carbon Edge 1095 knife take no attachments, only camos, decals and stickers. The clip is LunchTime reading the Mobility details of a stock in Gunsmith.

Shared attachments and weapon levels

Each weapon earns Weapon XP as you use it and unlocks an attachment at each level, per the progression blog. The level count differs by weapon: 72 for the Han 86 and M4, 64 for the ISO Nightshade, 75 for the KG-7 Vulcan, 37 for the .50 GS (Oct 19 blog).

Attachments are shared. An attachment is unlocked once and is then available on every weapon that uses it, and a weapon level that would hand you an attachment you already own is skipped with a Bonus Level Up, the Oct 19 blog explains. Leveling one gun therefore speeds up the next one of the same family. Weapon levels and attachments earned in DMZ early access carried into Multiplayer at launch, and the two modes share progress, per the progression blog. Double Weapon XP Tokens speed this up; two of them are campaign rewards; see How to Level Up Fast.

Apex attachments

4:57 An Apex attachment is the final reward for leveling a supported weapon to its max. It is equipped separately and does not use one of the five slots, and it changes how the weapon plays: alternate fire modes, built-in equipment or a new role, the Oct 19 blog says. Most Apex attachments block a few slots.

Some examples from that blog:

• M4 Hurricane: a top-loading, high-capacity 5.7x28mm conversion with a higher fire rate; blocks Barrel and Magazine.
• Oden Sentinel: turns the Oden into a semi-auto sniper with bipod, suppressor and scope.
• VEL 46 Snap: a sling for very fast weapon swaps, and Quick Draw with Overkill.
• WZ.55 Striga Rampage: akimbo Strigas.
• Han X20 Skybreaker: a top-mounted 20mm airburst launcher with its own targeting optic.
• Mosin Harpoon: a spring-loaded bayonet you can launch and retrieve.

Every Apex attachment is in the tables on Weapons. Infinity Ward counted 28 at launch, against 19 in the beta. Some beta Apex attachments were early seasonal event items and are missing at launch; the launch patch notes say "They will return soon", and Events (which replace Weekly Challenges in Season 1) will award Apex attachments among other rewards. Game Rant notes that a Kastov 545 Apex "is not available in Modern Warfare 4" yet.

The Apex names changed between reveal and launch. Activision's Aug 21 blog called some of them "Outlaw" (Mojave), "9&12" (Sang), "Hunter" (ISO) and "Shroud" (X-58 Nyx); the Oct 19 blog names them Mojave Lawless, SANG Breach, ISO Trace and X-58 Void.

Gunny, the attachment optimizer

5:27 Gunny (short for Gunnery Sergeant) sits in Create-a-Class and in the Gunsmith at the DMZ Forward Operating Base. It builds suggested Short Range, Balanced and Long Range versions of a weapon from the attachments you have unlocked, the Oct 19 blog says. It is a quick start before you have the attachments the Best Loadouts call for.

Other Gunsmith features

• Optic Rail Placement (new): slide an optic along the rail, a purely cosmetic change previewed from the aiming view.
• Thermal reticles: custom reticles on thermal optics come with different thermal effects.
• Saving builds: since launch you save a build in Gunsmith by hand; builds edited during a match save automatically.
• Reticles unlock with aim-down-sights kills on an optic, and progress is shared across modes and weapons that use that optic (progression blog).
• Firing Range: one in Multiplayer and one at the DMZ base, with dummies at 10, 25, 50 and 100 meters, moving targets, a recoil plate and readouts for accuracy, damage and time to kill (Oct 19 blog).

Sources: Call of Duty launch patch notes, unless named.

Weapon Prestige

At max level a weapon unlocks its Apex attachment and opens Weapon Prestige, per the progression blog. Entering Weapon Prestige 1 resets the weapon to Level 1 and relocks its attachments, except Apex attachments and blueprint attachments; it does not relock shared attachments on your other weapons, and blueprints, camos, reticles and cosmetics stay. A Prestiged weapon unlocks its attachments in the classic way, one level at a time, the launch patch notes add.

Reaching max level again puts the weapon in Weapon Prestige Master, which keeps leveling without another reset and adds a Prestige icon in Gunsmith and the Killcam. The Prestige camos are all forms of Pyroclast: Pyroclast at Weapon Prestige 1 Level 1, Pyroclast Terminus at Weapon Prestige 1 max level, Pyroclast Scatter at Weapon Prestige Master Level 150 and Pyroclast Cascade at Level 250 (progression blog). The Oct 23 and Oct 24 fixes stopped camos and Apex attachments from appearing locked after a Weapon Prestige. More on Prestige and Camos.

Blueprints

A blueprint is a premade weapon with its own look and attachments. One bought in the Store or earned in a Battle Pass makes its base weapon available at once, whatever your level, per the progression blog. Blueprint attachments survive a Weapon Prestige.

Blueprints also come from:

• Prestige: several Prestige levels award one, such as the Mosin-Nagant "The Vet" at Prestige 1 and the M4 "141" at Prestige 8 (Prestige).
• The Vault Edition: its Signature Weapon Collection holds Kastov 762 "Voltspine", ISO Nightshade "La Sombra Venenosa", Rezi 12 "Shattered Code", Oris 8.6 "Volt-Edge" and Combat Knife "Sombra Besada" blueprints, with attachments including an Apex, per Activision's editions blog (Editions and Pre-order Bonuses).
• The Battle Pass and BlackCell (Battle Pass and BlackCell).

No weapon blueprints are among the 16 campaign mission rewards, Game Rant's campaign rewards list notes.

Frequently asked questions

How many attachments can you use in MW4? In Call of Duty: Modern Warfare 4 a Multiplayer build takes five attachments, plus the weapon's Apex attachment, which does not use a slot.

How do you unlock Apex attachments in MW4? Level a weapon to its max level in MW4; the Apex attachment is the final weapon-level reward. Some will also come from Events, Infinity Ward says.

Are attachments shared between weapons in MW4? Yes. Each MW4 attachment is unlocked once and works on every weapon that takes it, and levels that would repeat one give a Bonus Level Up instead.

What is Gunny in MW4? Gunny is MW4's attachment optimizer in Create-a-Class and the DMZ base Gunsmith; it builds Short Range, Balanced and Long Range setups from your unlocked attachments.

What does Weapon Prestige reset in MW4? MW4's Weapon Prestige resets that weapon to Level 1 and relocks its own attachments, but keeps Apex and blueprint attachments, camos and cosmetics, and other weapons keep their shared attachments.

Can you customize launchers in MW4? No. MW4's four launchers and the knife take no attachments; only their camos, decals and stickers change.

Sources

• Ready for Launch: All Modern Warfare 4 Operators, Weapons, Equipment, and Multiplayer Create-a-Class Features, Call of Duty, Oct 19, 2026
• Ready for Launch: Modern Warfare 4 Progression and Prestige, Call of Duty, Oct 19, 2026
• Modern Warfare 4 Multiplayer: Movement, Gunplay, Modes, & Maps, Call of Duty, Aug 21, 2026
• Call of Duty: Modern Warfare 4: All Game Editions and Pre-order Benefits Detailed, Call of Duty, May 28, 2026
• Call of Duty: Modern Warfare 4 Launch Patch Notes, Infinity Ward, Oct 24, 2026
• Best Loadouts In Call Of Duty: Modern Warfare 4 Multiplayer, GameSpot, Oct 23, 2026
• Best Meta Kastov 762 Loadout in COD Modern Warfare 4, Game Rant, Oct 25, 2026
• Modern Warfare 4: Campaign Early Access Now Live, Call of Duty, Oct 16, 2026
• All Campaign Rewards in Modern Warfare 4, Game Rant, Oct 19, 2026
• Call of Duty Modern Warfare 4 (2026) Multiplayer - 15 Things You Need To Know Before You Buy, GamingBolt, Oct 11, 2026 (video)
• Top 5 Meta Weapons to Use for Modern Warfare 4, LunchTime, Oct 23, 2026 (video)