Secondary Weapon

Secondary weapons are backup, sometimes weaker weapons, found in the secondary slot. At first they're were limited to Sidearms only in Call of Duty 4: Modern Warfare and Call of Duty: World at War, but It's sequel expanded that into Secondary Weapons, including: and
 * Launchers, such as the RPG-7 or AT4
 * Shotguns
 * Handguns, or more commonly referred as Pistols.
 * Machine Pistols
 * The One Man Army bag in Modern Warfare 2.

To use the secondary, the player simply has to swap from the primary weapon using the Swap Weapons button. The speed of the swap ranges from each classification of Secondary Weapon, Pistols being the fastest and Launchers being the slowest.

The Secondary Weapon is mainly used as a advantage of reloading, as certain moments in time won't allow you to reload without taking many hits or even dying. Each Secondary also has its own amount of Attachments (excluding Launchers) and usage, such as the G18 being used in typical Sniper Classes in case an unwelcome guest decides to attempt an ambush, or the AA-12 can be used to quickly make haste and wipe a room out to capture an objective.

Overview

 * Pistols can be used as a quick finisher as these Secondaries have the fastest swap time out of the 4 Secondary Weapon groups.
 * Machine Pistols are frequently used in CQC (Close Quarters Combat) to midrange, as they have high damage or rate of fire but limited range.
 * Shotguns are used as a quick blow to enemies, and even earn Double to Multi-kills, as it's tough to survive a blow from a Striker or SPAS-12 without the aid of the Deathstreak Painkiller.
 * Launchers are either a type of Splash Damage Secondary, or an Anti-Air Secondary; The RPG-7, AT-4 and Thumper make use of a large explosive radius while the Stinger and Javelin are the Anti-Air Launchers (the Javelin is also capable of locking onto ground targets albeit taking longer to get there than the RPG-7 and Thumper).

Tips

 * The Perk Last Stand only allows the use of Pistols and in Modern Warfare 2, the M93 Raffica. If you are to go into Last Stand with any other Secondary Weapon, you'll immediately pull out an M9 as a replacement.
 * The Perk One Man Army replaces the Secondary Weapon slot, so keep in mind that you will only be allowed to switch classes, and if you are to run out of ammo, either find a place to hide and swap classes, or pick up a new weapon.
 * Pistols have a high Firecap, so it's easy to spam fire and catch a kill with one.
 * All Secondary Weapons, excluding Launchers, may be equipped with an attachment, or two with Bling Pro. Some typical attachments are:
 * Pistols - Akimbo or Tactical Knife
 * Machine Pistols - Akimbo or Extended Mags
 * Shotguns - Grip or Red Dot Sight
 * Don't rely solely on Secondary Weapons, as Primary Weapons generally are better overall. However, primary weapons specialising in only one aspect of combat may be less advantageous to use than a secondary weapon in some circumstances, eg a pistol is better than a sniper at cqb and the M93 Raffica is better than many SMGs at long range fighting.