MW3 Conversion Kits And Aftermarket Parts - How To Unlock Them

To keep things exciting, Call of Duty introduces new features each year. One of these in Modern Warfare 3 is Aftermarket Parts and Conversion Kits.

These parts and kits let players upgrade their beloved weapons into even more powerful tools. They add more diversity to the game, but getting them isn't a walk in the park. You'll need to earn a lot of XP, so be sure to use those double weapon XP tokens and get ready to level up.

Here's what you need to know about Aftermarket Parts and Conversion Kits in MW3.

What Are Conversions Kit in MW3?

Conversion Kits are add-ons that completely transform a weapon, sometimes in wild ways. For example, the JAK Ferocity Carbine Kit turns the Renetti pistol into an SMG.

New Conversion Kits keep coming each season, often as rewards for completing weekly challenges. But remember, your weapon needs to be max level to use them.

It’s smart to level up all your guns because more Aftermarket Parts will be added over time. You never know which one might become super powerful and shake up the meta.

These new parts unlock all sorts of cool stuff, like new optics, or even turning a shotgun into a rapid-fire rifle.

How To Unlock Conversion Kits in MW3

Once your weapon hits max level, you can unlock Aftermarket Parts and their Conversion Kits through challenges. To add Conversion Kits to your weapon, you first need to max it out to open up the slots.

Leveling up your guns quickly will help with this, and completing specific challenges is key to unlocking the Conversion Kits for each slot.

These challenges usually pop up as Weekly Challenges every Wednesday during MW3 seasons, so make sure to jump in and tackle them to unlock the latest upgrades.

How To Unlock Aftermarket Parts and Conversion Kits Fast

Since most conversion kits and aftermarket parts require you to complete a certain number of weekly challenges, this process can get a bit frustrating.

We can help you unlock aftermarket parts fast via our MW3 Aftermarket Parts unlock service. Simply select the Aftermarket parts you want purchased and we'll assign a pro player to unlock them for you while you chill.

What Is the Best Conversion Kit in MW3?

At the time of writing this article, the best conversion kits are in my opinion:

JAK Tyrant 762 Kit

WSP Akimbo Brace Stock

JAK Beholder Rifle Kit

JAK Maglift Kit

All MW3 Aftermarket Parts and Conversion Kits

I will now list all MW3 aftermarket parts and conversion kits below.

MW3 Season 3 Aftermarket Parts and Conversion Kits

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, week 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, week four 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:

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:

JAK Atlas Kit (AMR9)

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

How to unlock:

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

MW3 Season 2 Aftermarket Parts and Conversion Kits

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 Reaper (Underbarrel)

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)

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)

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 (Holder 26)

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)

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

MW3 Season 1 Aftermarket Parts and Conversion Kits

JAK Purifier

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 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

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)

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)

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

How to unlock: Season one, week five weekly challenge

The Ettin (AMR9)

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)

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

MW3 Preseason Aftermarket Parts and Conversion Kits

JAK Raven Kit (MCW)

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)

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 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 (Pulemyiot 762)

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

How to unlock: Armory Unlock

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

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)

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 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 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)

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