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Call of Duty: Modern Warfare 3has added two new weapons in Season 6, an LMG and battle rifle. The former weapon, the Kastov LSW, is arguably the strongest LMG in the game for aggressive playstyles. It has the best tactical stance accuracy out of all LMGs, making this weapon a CQC monster with the right attachments.
Thanks to some unique attachment options, you can turn the Kastov LSW into the ultimate run-and-gun weapon for Multiplayer and Warzone. Let’s go over how to unlock this weapon and showcase some of the LSW’s best attachment combinations, buffing this weapon’s tactical stance accuracy and mobility.
Updated June 03, 2025, by Charles Burgar:The Kastov LSW’s notable underbarrel grip, the Bracefire-HC Grip, has caught a massive nerf in Season 6. You can no longer use Tac Stance with this underbarrel equipped, which fundamentally changes how you build the Kastov LSW. We’ve updated this guide with a more accurate build that offsets the recent changes.
How To Unlock The Kastov LSW
The Kastov LSW can be unlocked through theSeason 6 Battle Pass.You’ll find this weapon in Sector 09, which will take roughly20 Battle Pass Tokensto reach from the starting point. Battle Pass Tokens are unlocked by earning XP in MW3, which can be from any main playlist (MP, Warzone, and MWZ).
Once Season 6 ends, you will be able to unlock the Kastov LSW from theArmory Unlocks system.
Best Kastov LSW Build
The Kastov LSW’s unique underbarrel attachment, theBracefire-HC Grip,allows you to build for absurd strafe speeds at the cost of ADS accuracy.You can’t build for Tac Stance with this attachment, so you’ll need to spec heavily into close-range gunfights. We do this through theBombast T54 Short BarrelandBroadside Stock, greatly buffing the gun’s handling stats.
Since we can’t modify the accuracy directly, we use our remaining attachments to lower the gun’s recoil. The Quartermaster Suppressor and Weave-L7 Grip mitigate your recoil enough to make short-range engagements fairly consistent.
Loadout Recommendations
With such a high ADS strafe speed, it’s a good idea to use theStalker Bootson this build. You’ll strafe significantly faster with these boots equipped. We pair this with theCompression CarrierVest to gain Tac Mask and Compression Plate for free, two S-tier perks for aggressive playstyles. Throw onGhostto stay off enemy radar andCommando Glovesto lower the gun’s high sprint-to-fire delay.
