Call of Duty Modern Warfare 3 Cheats

Multiplayer unlockables

Level 5: Throwing Knife
Level 6: SCAR-L (assault rifle)
Level 8: SPAS-12 (shotgun)
Level 10: P99 (handgun)
Level 11: Blind Eye perk
Level 12: Dragunov (sniper)
Level 13: Scrambler (tactical)
Level 14: PKP Pecheneg (LMG)
Level 15: Hardline perk
Level 15: Revenge (death streak)
Level 16: MP9 (machine pistol)
Level 18: CM901 (assault rifle)
Level 19: Sitrep perk
Level 20: Specialist (strike package)
Level 21: EMP Grenade (tactical)
Level 22: A550 (sniper)
Level 22: Extreme Conditioning perk
Level 24: Javelin (launcher)
Level 26: AA-12 (shotgun)
Level 27: Assassin perk
Level 28: PP90M1 (SMG)
Level 29: Smoke Grenade (tactical)
Level 30: MP412 (handgun)
Level 30: Steady Aim perk
Level 32: Type 95 (assault rifle)
Level 32: Final Stand (death streak)
Level 36: Skorpion (M. Pistol)
Level 37: Bouncing Betty (anti personnel mine)
Level 38: P90 (SMG)
Level 39: Scavenger perk
Level 40: Stinger (Launcher; vehicle lock-on only)
Level 42: G36C (assault rifle)
Level 44: RSASS (sniper)
Level 45: Trophy System (deflects enemy explosives/missiles)
Level 46: .44 Magnum (handgun)
Level 47: Overkill perk
Level 48: Striker (shotgun)
Level 50: ACR 6.8 (assault rifle)
Level 51: Martyrdom (death streak)
Level 52: XM25 (launcher)
Level 53: Claymore (anti personnel mine)
Level 54: MK46 (LMG)
Level 55: Dead Silence perk
Level 56: PM9 (SMG)
Level 57: Dead Man's Hand (death streak)
Level 58: Five Seven (handgun)
Level 60: MK14 (assault rifle)
Level 61: Tactical Insertion (marker to place your next re-spawn)
Level 62: Model 1887 (shotgun)
Level 64: M320 GLM (launcher)
Level 66: MSR (sniper)
Level 68: AK-47 (assault rifle)
Level 69: C4 Explosives
Level 70: G18 (machine pistol)
Level 71: Hollow Points (death streak)
Level 72: M60E4 (LMG)
Level 74: MP7 (SMG)
Level 76: Desert Eagle (handgun)
Level 77: Portable Radar (shows enemy movement within its radius)
Level 78: FAD (assault rifle)
Level 80: RPG-7 (launcher)

Prestige rewards

Extra Custom Class

2. Double XP (2 hours)

3. Double Weapon XP (2 hours)

4. Regular Package (title and emblem)

5. Unlock Gear (unlock a weapon, equipment, or perk permanently, no matter how many times you Prestige; available after the 1st Prestige)

6. Hardened Package (title and emblem; reach 5th Prestige)

7. Veteran Package (title and emblem; reach 10th Prestige)

8. Reset All Stats (reach 10th Prestige)

Killstreak bonuses

Assault Strike Package

UAV: 3 kills
Care Package: 4 kills
I.M.S. (Intelligent Munitions System): 5 kills
Predator Missile: 5 kills
Sentry Gun: 5 kills
Precision Airstrike: 6 kills
Attack Helicopter: 7 kills
Strafe Run: 9 kills
Little Big Guard: 9 kills
Reaper: 9 kills
Assault Drone: 10 kills
AC-130: 12 kills
Pave Low: 12 kills
Juggernaut: 15 kills
Osprey Gunner: 17 kills

Specialist Strike Package

One extra perk: 2 kills
Two extra perks: 4 kills
Three extra perks: 6 kills
All perks: 8 kills

Support Strike Package

Weapons, attachments, equipment, and camouflage

The following is a list of the primary weapons, secondary weapons, attachments, equipment, and camouflage in the game, along with the level they are unlocked at in Multiplayer mode:

Assault Rifles

M4A1
M16A4 - 3 round burst
SCAR-L
CM901
TYPE 95 - 3 round burst (Level 32)
G36c (Level 42)
ACR 6.8 (Level 50)
MK14 - Semi-automatic (Level 60)
AK-47 (Level 68)
FAD (Level 78)

Sub Machine Guns

MP5
UMP45
PP90M1
P90 (Level 38)
PM-9 (Level 56)
MP7 (Level 74)

Light Machine Guns

L86 LSW
MG36
PKP Pecheneg
MK46 (Level 54)
M60E4 (Level 72)

Sniper Rifles

Barrett .50 Cal
L118A (bolt action, looks similar to the L96 from Call Of Duty: Black Ops)
Dragunov
AS50
RSASS (Level 44)
MSR (Level 66)

Shotguns

USAS 12
KSG 12
SPAS 12
Striker - Semi-auto (Level 48)
Model 1887 (Level 62)
AA-12

Machine Pistols

FMG9
MP9
Skorpion (Level 36)
G18 (Level 70)

Handguns

USP .45
P99
MP412
.44 Magnum (Level 46)
Five Seven (Level 58)
Desert Eagle (Level 76)

Launchers

SMAW
Javelin
Stinger (Level 40)
XM25 (Level 52)
M320 GLM (Level 64)
RPG (Level 80)

Lethal

Frag Grenade
Semtex Grenade
Throwing Knife
Bouncing Betty Grenade (Level 37)
Claymore (Level 53)
C4 (Level 69)

Tactical

Flash Grenade
Concussion Grenade
Scrambler (like a Jammer)
EMP Grenade
Smoke Grenade
Trophy System (tripod sensor that deflects explosive sent in its direction) (Level 45)
Tactical Insert (Level 61)
Portable Radar (Level 77)

Attachments

Red Dot Sight
Silencer
Grenade Launcher
ACOG
Heartbeat Sensor
Hybrid Sight
Extended Magazines
Thermal Scope
Rapid Fire
Hamr Scope
Holographic Sight
Grip
Variable Zoom Scope

Camouflage

Classic
Snow
Multicam
Digital Urban
Hex
Choco
Snake
Blue
Red
Autumn
Gold