A Call of Duty operator takes cover behind a car in MW3 multiplayer.
Image via Activision

All Aftermarket Parts and Conversion Kits in MW3

These can completely change a gun.

With yearly releases, Call of Duty needs to change things up to keep it fresh. One of the new features in Modern Warfare 3 is Aftermarket Parts and Conversion Kits.

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These parts and kits allow CoD players to transform their favorite weapons into new threats. They increase the overall variety in the game, but unlocking them is far from easy. You’ll need plenty of XP in the process, so save up those double weapon XP tokens and start gaming.

Here’s all there is to know about Aftermarket Parts and Conversion Kits in MW3.

How to unlock Conversion Kits in MW3

Burst-fire holger Aftermarket Part in MW3.
Just one of the JAK conversion kits available in MW3. Screenshot by Dot Esports

Aftermarket Parts and their Conversion Kits are unlocked through challenges once a weapon reaches max level. If you’re looking to upgrade your weapon with Conversion Kits, you’ll first need to get it to max level just to unlock its respective slots.

The fastest ways to level up guns should speed up this process, and you’ll also need to complete certain challenges to unlock the Conversion Kits that will go into the slots that share the same name.

These challenges are often part of Weekly Challenges each week throughout MW3’s seasons.

What are Conversion Kits in MW3?

Conversion Kits are attachments that transform a weapon while defying the laws of physics. Conversion Kits completely change the weapon at times, like the JAK Ferocity Carbine Kit for the Renetti, which turns it from a burst pistol into an SMG.

New Conversion Kits will be added throughout each season, mostly through weekly challenge completions. But remember, to use a Conversion Kit on a specific weapon, that weapon must be max level.

It’s worth grinding every gun in the game to maximize their level because new Aftermarket Parts will be added over time, and you never know which one will be overpowered at launch and take over the meta when it releases.

These new parts and attachments unlock all sorts of cool stuff like new optic sights, a part that turns a shotgun into a full-auto battle rifle, or even an underbarrel chainsaw like something out of Gears of War. Yeah, let’s have some fun.

Here are all the Aftermarket Parts and weapon kits currently available in MW3.

Aftermarket Parts and Conversion Kits in MW3 season zero

JAK Raven Kit (MCW)

A screenshot of the JAK Raven Kit, a standard AR.
She’s got a pretty camo. Screenshot by Dot Esports

“Versatile and modular, this .300 conversion of the MCW can be adapted to hit hard in nearly every combat scenario.”

  • How to unlock: Season zero, week one challenge

JAK Heretic Carbine Kit (MTZ-762)

A screenshot of the JAK Heretic Carbine Kit (MTZ-762).
A full-auto beast. Screenshot by Dot Esports

“This powerful, 7.62 AR was crafted to deliver exceptional damage with moderate recoil.”

  • How to unlock: Armory Unlock

Broodmother .45 Kit (WSP-9)

A screenshot of the Broodmother .45 Kit (WSP-9).
Get up close and personal. Screenshot by Dot Esports

“A high-damage conversion kit that rides the line between SMG and AR with hard-hitting .45 Auto rounds.”

  • How to unlock: Armory Unlock

JAK Annihilator Bullpup Kit (Pulemyot 762)

A screenshot of the JAK Annihilator Bullpup Kit (Pulemyot 762).
Big, big, bullpup power. Screenshot by Dot Esports

“A modified, bullpup LMG that provides superior maneuverability while still delivering heavy and consistent fire.”

  • How to unlock: Armory Unlock

XRK IP-V2 Conversion Barrel Kit (COR-45)

A screenshot of the XRK IP-V2 Conversion Barrel Kit (COR-45).
Super-fast fire rate. Screenshot by Dot Esports

“This carbine conversion kit for the COR-45 allows for optics and underbarrel attachments. It also introduces binary fire which effectively doubles the fire rate.”

  • How to unlock: Armory Unlock

JAK Ferocity Carbine Kit (Renetti)

A screenshot of the JAK Ferocity Carbine Kit (Renetti).
Like an SMG in your back pocket. Screenshot by Dot Esports

“This heavy carbine kit converts the Renetti pistol into a compact and maneuverable SMG. Allows for optics, stocks, and underbarrel attachments.”

  • How to unlock: Armory Unlock

JAK Nightshade Rifle Kit (DG-58 LSW)

A screenshot of the JAK Nightshade Rifle Kit for the DG-58 LSW in MW3.
From LMG to AR. Screenshot by Dot Esports

“A 5.8x42mm assault rifle that hits hard and doesn’t ask questions. In the right hands, this rifle can win almost any engagement.”

  • How to unlock: Season zero, week two challenge

WSP Akimbo Brace Stock Kit (WSP Swarm)

A screenshot of the WSP Akimbo Brace Stock Kit for the WSP Swarm in MW3.
Unload with some big magazine attachments. Screenshot by Dot Esports

“A brace stock used to keep the weapon stable when firing akimbo.”

  • How to unlock: Season zero, week three challenge

MCW 6.8 Full Auto Conversion (MCW 6.8)

A screenshot of the Full-Auto Conversion Kit for the MCW 6.8 in MW3.
Not the best, but not bad. Screenshot by Dot Esports

“Converts the MCW 6.8 into a full-auto marksman rifle.”

  • How to unlock: Armory Unlock

Cronen INTLAS MSP-12 (Optic)

“A quick and snappy dot optic with an integrated laser for added accuracy”

  • How to unlock: Armory Unlock

INTLAS CAS-14 (Optic)

“This 2.5x optic is ideal for medium ranges and comes with an integrated laser.”

  • How to unlock: Armory Unlock

Aftermarket Parts and Conversion Kits in MW3 season one

JAK Purifier

A weapon with the JAK Purifier underbarrel flamethrower mod equipped is inspected.
JAK Purifier. Image via Activision

“Equip an underbarrel flamethrower” on the MCW, MTZ-556, Holger 556, DG-56, SVA 545, RAM-7, MTZ-762, BAS-B, Sidewinder, and Riveter.

  • How to unlock: Season one battle pass

JAK Headhunter Carbine Conversion (Rival-9)

Rival-9 Aftermarket Part in MW3
An SMG/AR hybrid. Screenshot by Dot Esports

“Rival Assault Rifles with this three-round burst conversion kit that excels at midrange combat.”

  • How to unlock: Season one, week one weekly challenge

JAK Bullseye (Optic)

“Very low-profile dot Optic. Limited interference from framework offers an exceptionally clear sight picture.”

  • How to unlock: Season one, week two weekly challenge

JAK Beholder Rifle Kit (TYR)

JAK Beholder Rifle kit for the TYR in MW3.
A handheld sniper. Screenshot by Dot Esports

“A long and heavy barrel that offers the best increase to range. Improves recoil control and damage range, converting this Handgun into a single-shot Rifle.”

  • How to unlock: Season one, week three weekly challenge

KR INTLAS LSJ-3 (Optic)

“A 4x optic with an integrated laser for faster targeting and accurate results.”

  • How to unlock: Season one, week four weekly challenge

JAK Signal Burst (Holger 556)

Burst-fire holger Aftermarket Part in MW3.
An elite AR, now burst-fire. Screenshot by Dot Esports

“A conversion kit designed for accuracy and controllability with four-round bursts.”

  • How to unlock: Season one, week five weekly challenge

The Ettin (AMR9)

The Ettin AMP Conversion Kit for the AMR9 in MW3.
Double the barrels, double the fun? Screenshot by Dot Esports

“Available for the AMR9 SMG, this kit creates two stacked barrels that fire simultaneously. This offers twice as much down-range damage at the cost of some accuracy.”

  • How to unlock: Season one, week six weekly challenge

JAK Thunder LMG Kit (Sidewinder)

JAK Thunder LMG kit
Have you tried this one yet? Screenshot by Dot Esports

Dominate lanes and hold objectives with this LMG conversion kit for the Sidewinder Battle Rifle that brings a large capacity magazine and ramps in fire rate the longer you hold down the trigger.

  • How to unlock: Sector A21 in the season one battle pass

JAK BFB

A compensator attachment for “many Assault Rifles, Submachine Guns, Battle Rifles, Marksman Rifles, and Sniper Rifles.”

  • How to unlock: Sector A21 in the season one battle pass

Aftermarket Parts and Conversion Kits in MW3 season two

Season two aftermarket parts in MW3
Add all of them to your collection. Image via Activision

JAK Burnout (Holger 26)

“Gives the Holger a select fire mode called JAK Burnout that provides a dramatically increased fire rate but can overheat and expand the barrel, introducing spread.”

  • How to unlock: Season two battle pass

JAK Tyrant 762 Kit (Longbow)

“This caliber Conversion Kit swaps out the receiver and magazine to accommodate 7.62 BLK ammunition for a harder-hitting, subsonic weapon.”

  • How to unlock: Season two, week one weekly challenge

JAK Limb Ripper (underbarrel)

JAK Limb Ripper underbarrel in MW3
Is this Gears of War? Image via Activision

“Unrivaled at creating close-quarters carnage, this underbarrel chainsaw makes quick and messy work of anyone foolish enough to stand in your way.”

  • How to unlock: Season two, week two weekly challenge

JAK Maglift Kit (Haymaker)

JAK Maglift Kit in MW3
A really, really, really big magazine. Screenshot by Dot Esports

“This weapon modification reinforces the magwell, bolt, and trigger assembly to accommodate the extra-large drum magazine.”

  • How to unlock: Season two, week three weekly challenge

JAK Glassless Optic (optic)

JAK Glassless Optic in MW3
Reminiscent of the past. Screenshot by Dot Esports

“This small, glassless reflex optic offers a crisp and clear sight picture for snappy target acquisition.”

  • How to unlock: Season two, week four weekly challenge

JAK Burnout Kit (Holger 26)

JAK Burnout Kit season 2 MW3 Aftermarket Part
A new LMG? Image via Activision

“Introduces an adverse fire functionality that pushes the weapon to extreme fire rates but hurts accuracy as the barrel overheats.”

  • How to unlock: Challenge in Sector B21 of season two battle pass

JAK Backsaw Kit (Holger 556)

JAK Backsaw Kit in MW3
It’s a bit funny-looking. Screenshot by Dot Esports

“A Conversion Kit focused on making the Holger 556 more maneuverable. The stock is removed entirely for faster, more agile tactics.”

  • How to unlock: Season two, week six weekly challenge

JAK Outlaw-277 Kit (BAS-B)

“This Conversion Kit transforms the BAS-B into a lever-action rifle, slowing fire rate but vastly improving accuracy for deadlier precision.”

  • How to unlock: Season two, week seven weekly challenge

Aftermarket Parts and Conversion Kits in MW3 season three

MW3 Season 3 Aftermarket Parts
Eight new ones to strive for. Image via Activision

JAK Shadow Titan Kit (Bruen Mk9)

“Converts the Bruen Mk9 into a compact and integrally suppressed light support weapon chambered in 300 blackout.”

  • How to unlock: Season Three, week one weekly challenge

JAK Jawbreaker (KV Broadside)

“Converts this Shotgun into a hard-hitting, automatic Battle Rifle.”

  • How to unlock: Season Three, week two weekly challenge

JAK Cutthroat (Stock)

“This 3D-printed stock provides an unrivaled combination of speed and stability while aiming down sights.”

  • How to unlock: Season Three weekly challenge

JAK Revenger Kit (BP50)

“This conversion kit turns the BP50 into a CQC legend. A 9mm caliber conversion with shortened receiver and high-capacity magazine.”

  • How to unlock: Season Three weekly challenge

JAK Patriot (M16)

“Converts the M16 into a fully automatic rifle with a heavy ported barrel built to provide superior recoil control and firing aim stability.”

  • How to unlock: Season Three weekly challenge

Wardens (Lockwood Mk2)

“Relive the glory days, stir up the hornet’s nest, and take down your enemies, leaving no loose ends with these museum-worthy akimbo lever-action shotguns.”

  • How to unlock: Season Three weekly challenge

JAK Atlas Kit (AMR9)

“Converts the AMR9 into an extremely lethal and accurate 5-round burst carbine chambered in 556.”

  • How to unlock: Season Three weekly challenge

Photonic Charge Barrel (MORS)

“This hyper-advanced barrel is more than simply a barrel. Holding the trigger charges the rifle and releasing fires a single, high-power energy projectile.”

  • How to unlock: Redacted

This article will be updated when more Aftermarket Parts and kits are added to MW3.


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Author
Scott Duwe
Staff Writer & Call of Duty lead. Professional writer for over 10 years. Lover of all things Marvel, Destiny 2, Metal Gear, Final Fantasy, Resident Evil, and more. Previous bylines include PC Gamer, Red Bull Esports, Fanbyte, and Esports Nation. DogDad to Yogi the Corgi, sports fan (NY Yankees, NY Jets, NY Rangers, NY Knicks), Paramore fanatic, cardio enthusiast.
Author
Gökhan Çakır
Gökhan is a Staff Writer and Fortnite Lead at Dot Esports. Gökhan graduated as an industrial engineer in 2020 and has since been with Dot Esports. As a natural-born gamer, he honed his skills to a professional level in Dota 2. Upon giving up on the Aegis of Champions in 2019, Gökhan started his writing career, covering all things gaming, while his heart remains a lifetime defender of the Ancients.