The FAL is most commonly used by the Brazilian Militia inTakedown. The variant used seems to be a LAR that has been modified with the addition of the surface-integrated rail.

It is unlocked at level 28 of Call of Duty: Modern Warfare 2's multiplayer.

Ironically, the FAL (Fusil Automatique Leger), which means "Light Automatic Rifle" is limited to semi-automatic fire in both single player and multiplayer. This, despite its power, reduces its effectiveness at close range. Using the shotgun attachment, or carrying an aggressive secondary weapon, can help mitigate this.  A strategy for using the FAL is to have an ACOG/thermal sight equipped, making it a rather effective mid range sniper rifle, having 20 rounds per magazine along with quick reloading. It is not as effective as a long range sniper rifle as it takes three shots to kill at long range and the shooter must pause briefly between shots to let recoil settle in order to be accurate giving the target a chance to find cover or escape. If fired as quickly as possible, without ACOG or Thermal, the FAL will recoil randomly leading to a decently tight circular grouping at short to mid-range. Because of the FAL's damage of 35-55, Stopping Power has minimal effect. It will always be a 2 hit kill at close range, and a 3-hit kill at long range, regardless of Stopping Power, with the exception of direct 1 hit headshot kills at close range, and 2 headshots at long range. For this reason, another tier 2 perk is recommended for this weapon. Having a silencer attached may also make it an effective stealth rifle.  It is also very effective on hardcore modes because of high damage.

Bling used with the FAL is also a good choice, as the FAL is semi-automatic, and you don't need Scavenger unless you are a trigger masher. Bling can add a shotgun and a sight; giving the weapon more powerful close range capabilities, given that the weapon does not fire in fully automatic.

Like the UMP45, the FAL is one of the few non-sniper weapons in the game that can kill in a maximum of three shots regardless of range, perks, or attachments.  This means that the FAL is actually quite good with Cold-Blooded and a Silencer, considering that all other Assault Rifles require a minimum of four shots at long range without Stopping Power.

The FAL is one of the most powerful weapons in the game, because it can fire at rate of up to 630 rounds per minute. The FAL can kill with 2 shots or one headshot at close range. This is right behind the SCAR because it fires 20 rounds less per second, but this is significantly reduced due to it being a semi-automatic weapon. The FAL trades its position with the SCAR for lower recoil, extremely controllable firing, and a quieter profile.

The FAL loses some of its damage drop-off with the Holographic Sight attached. Normally, the weapon would do 35 damage past 1700m, but with the holographic sight, this number is increased to 40 damage past 1600m. Knowing this, the gun becomes a 2 shot kill at any range when using a holographic sight, any kind of Bling including the holographic sight and Stopping Power.

The back of the FAL's iron sights sways when aiming down the sights. For some reason the Masterkey Shotgun attachment removes this swaying, possibly by adding bulk, making the weapon heavier but stable.

In Zombies mode, the FN FAL can be obtained from the mystery box. It comes with a 20 round magazine, moderate power and high accuracy. Due to the larger mag size and equal power, the FAL is considered superior to the M14, however its semi-auto fire mode and low damage compared to the other assault rifles means it is outclassed by other weapons such as the Commando or HK21 in anything later than the early rounds. When Pack-a-Punched it turns into EPC WN, and gains a Reflex Sight with a random reticule and switches to a three-round burst firing mode. 

Trivia

• On release the FAL was drastically less powerful than it was after the second patch.

• The FAL is considered a surplus weapon.  As most countries have replaced their FALs with imported or locally manufactured weapons, old FAL caches end up on the Black Market, which could explain how the Militia and Opfor are armed with so many, in addition to the local manufacture of the rifle.

• The ingame model is closer to the DSA58 OSW, as the magazine size and shape is too small to be a FAL magazine, and the DSA58 uses similarly shaped magazines, as well as possessing a charging handle on the side.

• The FAL has a unique reload animation, in that the fresh magazine is used to eject the spent magazine, before being placed in. This is known as "speedloading", and is a method that is more popularly used on the AK-47. This is not just for show, however, as the FAL has a comparatively fast reload time. In real life the used magazine falls on the ground if speedload is used, so that you would not be able to use the remaining rounds again. In the game it acts as if you had kept the used magazine with you so you can use the rounds in one of next reloads (the ammo count will not decrease for the used magazine).

• While reloading the FAL, the old magazine is always shown still containing a cartridge, even during an empty reload.

• The FAL is capable of fully-automatic fire; however as it was considered difficult to control while firing fully-automatic; the Commonwealth versions were limited to semi-automatic fire.

• The FAL serves the same purpose the G3 and the M14 did in Call of Duty 4, having both power and low recoil.

• The FAL is actually a Battle Rifle, as it fires a full power cartridge.  Other weapons of this nature include the SCAR-H, M14 EBR and G3.

• The FAL's magazine model is actually for 30 rounds while the default FAL holds only 20 (in multiplayer.) Attaching Extended Mags remedies this, although due to the high power, this attachment is not needed nor suggested.  In reality 20 round magazines are more common.

• Militia and Russian soldiers in campaign can fire the FAL fully automatically from around corners, but you cannot.

• When using the FAL with a Red Dot Sight, the bullet will not go right to the dot. The bullet hits a small amount below and to the right, but oddly the Holographic Sight works correctly.

• The FN-FAL is one of the most tested rifles in the world, having served in over 15 official conflicts and remaining in service with current guerilla forces.

• An interesting tactic for Hardcore mode is to use a Thermal Scope and use it like a semi-automatic sniper rifle, although with this method you will not get a ghillie suit.

• The FAL is the British SLR variant, the FAL uses a wooden stock and cover on the barrel, while the SLR uses plastic. Although the 50.00 version of the FN FAL uses plastic.
• The FAL is currently produced as the SA58 by DSA Inc. in the US and is available in newer configurations.
• The FAL in-game has a reciprocating charging handle, while the actual FAL does not.
• The FAL was ranked 5th on the Military Channel's top 10 combat rifles .