History

The L86A1 LSW is a magazine-fed automatic weapon originally intended to provide fire support at a fireteam level. It has a longer barrel than the L85A1 rifle and a bipod, shoulder trap and rear pistol grip, together with a shorter handguard. The extended barrel provides an increased muzzle velocity and further stabilises the bullet, giving a greater effective range. The weapon is otherwise identical to the L85 version on which it is based, and the same 30-rd magazines and sighting systems are used. Like the L85 rifle, it has a rate-of-fire selector on the left side behind the magazine housing, enabling either single shots or automatic fire.
 
The increased barrel length, bipod and the optical performance of the SUSAT gives the weapon excellent accuracy. From its inception, the L86 was a target of criticism on much the same basis as the L85. The LSW has the additional issue (shared by any light support weapon derived from a rifle, for example the heavy-barrel FN FAL) of its inability to deliver sustained automatic fire as it does not have a quick-change barrel, and is not belt fed.
 
The primary use of the LSW has shifted to that of a marksman's weapon within many infantry sections, capable of providing extremely accurate precision fire at ranges of over 600m. The role of a light support weapon is instead filled with the L110A1 FN Minimi which is a belt fed weapon with a quick-change barrel.
 
The L86A1 was upgraded to the L86A2 at the same time as L85A1 rifles were upgraded to L85A2 standards, undergoing the same set of modifications.

Singleplayer/Spec-Ops

Multiplayer

The L86 LSW is unlocked at Level 4 in Modern Warfare 3's multiplayer. It features a relatively high rate of fire, decently low recoil, and moderate-low damage.
 
Compared to the other LMGs, the main strengths of the L86 are the fast reload time (beaten only by the MG36), the fast rate of fire (beaten only by the MK46) and the lowest recoil among all the LMGs. When coupled with the Grip attachment or the Kick proficiency, the weapon's bullet spread improves massively, although the weapon will still visually kick. All combined, the L86 is capable of a large volume of accurate fire with minimal interruption from reloading.

Attachments

Attachments	Challenges	Icon
Reflex Sight	Get 60 kills while looking through a Red Dot Sight attached to a LMG.
Silencer	Get 15 kills with a Silencer attached to a LMG.
Grip	Get 60 kills with a Grip attached to a LMG.
ACOG Scope	Get 20 kills while looking through a ACOG Scope attached to a LMG.
Rapid Fire	Get 40 kills with Rapid Fire attached to a LMG.
Heartbeat Sensor	Get 40 kills with a Heartbeat Sensor attached to a LMG.
Holographic Sight	Get 40 kills while looking through a Holographic Sightattached to a LMG.
Extended Mags	Get 40 kills with Extended Mags attached to a LMG.
Thermal	Get 40 kills while looking through a Thermal attached to a LMG.

Proficiencies

Proficiency	Description	Icon
Kick	Kick Reduces recoil by 20%, allowing for steadier full-auto and faster recovery from shots.
Impact	Impact grants maximized penetration for any weapon. This is especially powerful on Assault Rifles and SMGs, as LMGs already have strong penetration, and Sniper Rifles are difficult to use for intentional walling shots.
Attachment	Allows the use of 2 Attachments. It is a solid all-around Proficiency, useful in many situations. This Proficiency is also notably useful for stealth builds, as it allows you to use a Silencer alongside any other Attachment. The Attachment Proficiency is also helpful if you are still getting comfortable with iron sights, as it allows you to take and optical Attachment and a second utility Attachment.
Focus	Reduces visual recoil by 50% when you are hit. Focus is very effective for SMGs and Shotguns. It is also helpful for ARs, as it can keep your shots on target when you enter a heads-up one-on-one firefight.
Speed	Improves movement speed by 10%, or one step up on the mobility scale. Speed is an important upgrade for LMGs and Riots Shields. It is less critical for Sniper Rifles, excepting the Barret and AS50, which are heavier and slower than other Sniper Rifles.
Stability	Reduces idle sway by 25%. Consider this to be an 'automatic' Breath for long-range combat. It is most useful on LMGs, as they need the enhanced accuracy for long-range shots, though ARs also benefit from it.

Challenges