Here you will find all the Call of Duty: Black Ops 2 multiplayer weapons for the Xbox 360, PlayStation 3, Wii U and PC versions. Unlike in previous Call of Duty games, the new Create-A-Class system allows you to choose your weapon loadout as you please - you can also opt-out and only use a knife, which gives you more room for perks and equipment.
Each primary weapon in BO2 can carry 2 attachments, but the limit can be increased to 3 with a Wildcard. Secondary weapons can only carry 1 attachment, but like with primary weapons, the amount can be increased with a Wildcard. You can carry one Lethal and Tactical equipment, but there's a slot for an extra.
Each gun in the game has its own level and gains experience when it's used. You'll need to gain experience with each gun to unlock new attachments, sight reticles, and camouflages. If you decide to Prestige, the guns won't reset and you'll be able to continue where you left off after you've unlocked them again.
Source: http://www.blackopsii.com/bo2/weapons-list/
Black Ops 2 (II) - Weapons List - Assault Rifles
Assault Rifles are the workhorse weapons of Black Ops 2. They are ideal for medium-range engagements, and are effective at close or long range. You can take an Assault Rifle to any map and game mode and expect to do well. With the right attachments, you can configure your AR to perform better at different ranges or in different game modes.
M8A1
SCAR-H
AN-94
SIG556
Type 25
SA-58
SMR
M27
MTAR
Black Ops 2 (II) - Weapons List - Shotguns
Shotguns are lethal close-range weapons, ideal for clearing rooms and patrolling urban areas with sharp corners and short engagement distances. Shotguns are devastating at close range, but they are literally useless at a distance. Unlike other weapons, which simply suffer reduced damage at long range, shotguns pellets simply vanish past their minimum damage range.
R-870 MCS
M1216
SAIGA-12
KSG
Black Ops 2 (II) - Weapons List - Light Machine Guns
LMGs are the heavy hitters of your arsenal. With large magazines, high damage and great penetration, they can used to cover an area extremely effectively. Consider LMGs to be the inverse of SMGs. While SMGs excel at close-range rapid assault, LMGs excel at locking down an area defensively.
MK 48
QBB LSW
LSAT
HAMR
Black Ops 2 (II) - Weapons List - Sniper Rifles
Capable of instantly dispatching a target at ultra-long range, Sniper Rifles are the perfect weapons for covering long lanes of fire. By moving quickly from location to location on open maps with a lot of cover, or by locking down the approach to an objective, you can make it extremely difficult for the enemy team to get close to you or an objective.
BALLISTA
SVU-AS
DSR 50
XPR-50
Black Ops 2 (II) - Weapons List - Sub Machine Guns
SMGs are the weapon choice for short-range firefights and any objective mode that demands mobility. They feature high movement speed, fast aim-down-sight (ADS) times, high rates of fire, and good hip-fire accuracy. SMGs are ideal for fast, aggressive assaults on objective targets, or flanking maneuvers on the enemy team.
MP7
SKORPION EVO III
PDW-57
CHICOM CQB
MSMC
VECTOR K10
Black Ops 2 (II) - Weapons List - Specials
The Assault Shield is an unusual 'weapon', an almost purely defensive tool that's effective in certain objective modes. It isn't recommended for general deathmatch modes. However, in objective modes the Assault Shield can be valuable in blocking an access route or providing cover from long-range fire while you claim an objective.
ASSAULT SHIELD
Black Ops 2 (II) - Weapons List - Launchers
Launchers are special weapons designed to take out air support, dispatch large groups of clumped-up enemies, and dig out campers out of small rooms. You can use the SMAW and RPG as anti-air or anti-ground, while the FHJ-18 AA is anti-air only. The CROSSBOW is primarily anti-infantry, though you can shoot at low-flying air support, albeit ineffectively.
SMAW
FHJ-18 AA
RPG
CROSSBOW
Black Ops 2 (II) - Weapons List - Pistols
Pistols are accurate weapons that pack a punch at close range and have very quick switch times. This allows you to switch out your primary weapon when you dump a magazine, and finish off wounded targets before they can reload. Because of this trait, Pistols are ideal backup weapons for SMGs or ARs, as they can help you come out on top in a close-range engagement when your ammo runs dry.
KAP-40
TAC-45
B23R
EXECUTIONER
FIVE-SEVEN
Black Ops 2 (II) - Weapons List - Lethal
Lethal equipment can clear a room or guard your back.
GRENADE
Grenades have a short fuse and can be 'cooked' before throwing it. Doing so allows you to airburst grenades, turning them into lethal targeted explosives.
COMBAT AXE
The COMBAT AXE is an instantly lethal thrown weapon that can be retrieved after embedding itself in an objective - or another player.
SEMTEX
The SEMTEX has explosive power identical to the grenade, but trades the ability to be cooked or rolled for a shorter fuse time and the ability to stick to any target. You can stick SEMTEX to walls, floors, ceilings, objectives, and even other players.
C4
The C4 is a manually triggered explosive that can be attached to any wall, ceiling, or convenient vehicle. You can detonate C4 by shooting it or using the detonator.
BOUNCING BETTY
The BOUNCING BETTY is a proximity explosive. When triggered, it launches itself into the air and detonates, causing an explosive blast in a 360-degree radius. It's possible to duck or go prone to avoid half or the entire explosion.
CLAYMORE
CLAYMORES are frontal-cone proximity explosives, detonating at ankle level. Proper placement of CLAYMORES is vital for full effectiveness.
Black Ops 2 (II) - Weapons List - Tactical
Tactical equipment grants you special combat capabilities.
SMOKE GRENADE
Useful for creating a smoke screen for moving across a covered lane of fire.
CONCUSSION
Powerful stun weapon that stagger enemies caught in the blast radius. It slows their movement and causes aim to sway wildly.
EMP GRENADE
Can disable and destroy deployed equipment - it's so powerful that it can also destroy low-flying air support within its blast radius.
SENSOR GRENADE
While it's active, it emits a radar ping that detects any enemies in its radius.
FLASHBANG
FLASHBANGS are powerful support tools, disabling enemies with a blinding flash of light that stops sprinting and causes total visual impairment if the grenade goes off with the target looking directly at it.
SHOCK CHARGE
Electrocutes and stuns enemies that get near it.
BLACK HAT
Allows you to hack equipment and Care Packages, or disable enemy vehicles.
TACTICAL INSERTION
Black Ops 2 (II) - Weapons List - Attachments
Attachments modify your weapon to suit your personal preferences, as well as the map or game mode you're playing.
ACOG
The ACOG (Advanced Combat Optical Gunsight) provides enhanced zoom at the cost of a slightly slower ADS time.
ADJUSTABLE STOCK
Allows you to move faster while aiming your weapon.
BALLISTICS CPU
Reduces your weapons idle sway when aiming.
DUAL BAND
Night vision scope with interlaced thermal overlay.
DUAL WIELD
Works like AKIMBO from the Modern Warfare series. DUAL WIELD allows you to equip 2 pistols, one in each hand, but you lose the ability to aim down the sight.
EXTENDED CLIP
Increases the ammo available to your magazine by 50%.
FAST MAG
Decreases the time it takes for you to reload your weapon. Every other reload is faster than normal, since 2 magazines are taped together.
FMJ
The FMJ (Full Metal Jacket) allows your weapons bullets to penetrate thicker surfaces.
FORE GRIP
Reduces your weapons recoil.
GRENADE LAUNCHER
Allows you to shoot grenades. It's a useful tool for clearing rooms or objectives.
HYBRID OPTIC
Allows you to toggle between a Red Dot and an ACOG-equivalent scope.
IRON SIGHTS
Removes the scope of your Sniper Rifle and replace it with an Iron Sight.
LASER SIGHT
Works like the Steady Aim perk by increasing your hip fire accuracy; it also makes you more visible to other players due to the laser.
LONG BARREL
Increases your weapons range.
MILLIMETER SCANNER
When aiming down the sight, the MILLIMETER SCANNER scans heat signatures every few seconds and allows you to see enemies through materials up to 25 meters.
QUICKDRAW
Increases your aiming speed.
RAPID FIRE
Increases your weapons rate of fire by 20%.
REFLEX
Replaces your weapons iron sight with a precision Red Dot Sight.
SELECT FIRE
Allows you to switch to burst or automatic fire at anytime.
SUPPRESSOR
Makes your weapon quieter and reduces muzzle flash. It also prevents you from showing up on the enemy radar every time you shoot.
TACTICAL KNIFE
Carry a tactical knife in your off hand for faster melee attacks.
TARGET FINDER
Identifies enemies and highlights them in red.
VARIABLE ZOOM
Sniper Rifle scope that has multiple levels of zoom.
Source: http://www.blackopsii.com/bo2/weapons-list/