Hardline

Hardline is a Tier 2 perk available in Call of Duty: Modern Warfare 2 and a Tier 1 perk featured in Call of Duty: Black Ops. It reduces the amount of kills required to gain a Killstreak reward by one.

Call of Duty: Modern Warfare 2
In Modern Warfare 2, it allows the player to gain their killstreak rewards with one less kill. For instance, if the player had UAV Recon, Care Package and Sentry Gun as killstreak rewards, rather than needing 3, 4 and 5 kills respectively, they would only need 2, 3 and 4 kills. It is useful with all classes, although especially useful with classes with guns which carry little ammo, or ammo which is used up quickly, such as the Vector, because it means fewer bullets are needed to gain killstreak rewards. Hardline Pro is unlocked after obtaining 40 killstreak rewards (not getting at least a 2 kill streak 40 times, as many may think), the easiest way to do this is set the player's killstreak rewards to require 3, 4 and 5 kills. The Pro version of the perk allows deathstreaks to be activated by one less death. For example, if the player has Final Stand as a deathstreak, requiring four deaths, with Hardline Pro the player only needs to die three times before the deathstreak is activated.

Call of Duty: Black Ops
Hardline returns as a Tier 1 perk in Black Ops.

Overview
Hardline reduces all killstreak requirements by one. Its pro version allows the player to "re-roll" the Care Package killstreak by double-tapping the action button, which will change its contents randomly. A Care Package can only be re-rolled once, and will always change its content.

Below is a table showing the default Care Package probabilities compared to the re-roll probabilities. As can be seen re-rolling favors middle killstreaks much more than Care Packages, while higher killstreaks are almost unchanged.

Hardline gives the player model a standard kevlar and helmet.

Pro Challenges

 * Share Packages – Share 10 Killstreak reward crates with teammates.
 * Multiple Killstreaks – Earn 7 killstreaks in one match while using Hardline.
 * Killstreak – Get 7 kills without dying in one match.

Trivia

 * The Perk emblem resembles the screen of an EKG machine, referring to the flat-line caused by death.
 * In Black Ops, the pro effect allows the player to get a second chance on any care package, etc., along with care packages dropped by enemies and teammates. Clever players can get easy killstreaks if a teammate allows them to take a package of little value, such as ammo. An old trick was to set the SAM Turret instead of the Care Package, as it would essentially become a 3 Killstreak Care Package. This, as well as the ability to 're-roll' the Sentry Gun and Valkyrie Rockets, was patched sometime between December 13th and 14th, 2010.
 * In the Black Ops singleplayer campaign, most of the non-player characters have a character model near-identical to that of the Hardline character model. However, most have the Scavenger backpack.
 * You cannot re-roll a package that is about to be taken, even if it is your own care package.