This is a guide to classes in MW3-MW2.
-Primary Weapon: Either an Assualt Rifle, SMG, LMG, Sniper Rifle, Riot Shield, or Shotgun(In MW3) that the player normally uses.
--Assault Rifle: An All-Around, usually Automatic weapon, with medium sized mags (20-60 rounds).
--SMG(Sub Machine gun): A Light, small, shorter-ranged weapon used for mobility and close-combat. Usually have medium damage and high fire-rates.
--LMG(Light Machine gun): A Heavy, big, medium-long range weapon with huge mags(Usually 100-200 rounds). Used for defending and picking of enemies, rather than charging objectives.
--Sniper Rifles: A Mega-High damaged(Usually a 1shot kill), extra long range weapon. Used for picking of enemies, one bullet at a time. Snipers usually stand in a high-up place, shooting whoever unfortunately falls into their view. However, if the miss, they risk giving away their position.
-- Riot Shield: A Shield that replaces a gun, deflecting bullets. Riot shielders can be taken down with sticky grenades or from the back.
-Secondary Weapon:A secondary gun, either a handgun, machine pistol, launcher, or shotgun(In MW2).
--Handgun: (Also called a Pistol or Sidearm) a very small, low mag, semi-automatic weapon with medium damage. Used in tight spaces or when unexpected enemies show up at an inconvenient time.
--Machine Pistol: An automatic pistol with medium sized mags.
-- Launcher: A heavy rocket launcher used to take out large areas of enemies or destroy air support.
--Shotgun: A semi-automatic used for taking out enemies at an extremely close range.
-Equipment: Something placeable or throwable, such as a grenade, throwing knife, trophy system, etc.
-Special grenade: A grenade used to put the enemy at a disadvantage, such as stunning them or blinding them temporarily.
-Perk: A Power-up that gives the players abilities such as Unlimited sprint, Increased bullet damage, Silent footsteps, or a farther knifing range. The player can choose three perks, one from each tier(blue, red, and yellow).
-Killstreak or Pointstreak- A reward obtained from getting a certain amount of kills without dying, such as a UAV, Care package, Attack Helicopter, EMP, etc.
That's what you need to know to make the perfect loadout in MW2-MW3.