Double Tap

Double Tap is a second tier perk in Call of Duty 4: Modern Warfare and Call of Duty: World at War that increases the rate of fire for all automatic weapons (exceptions being the W1200 shotgun, which speeds up the pumping animation, the M16A4, which hastens the speed of the burst firing, the R700 and M40A3, which increases the speed of the bolt cycling, and the M1014 in which case the delay between every shot is minimized. It has little practical effect on any other semi-automatic weapons to players without a speedy trigger finger (such as the SVT-40, G3, or M14. Some slower firing rifles such as the M1 Garand and the M1A1 Carbine may benefit greatly from this perk to a player with a fast triggerfinger).

Multiplayer Tactics
This perk is most effective on weapons that rely more on ROF than individual bullet damage, as well as close quarters weapons, but it has the disadvantage of emptying a weapon's magazine quickly and increasing recoil. It cannot be reasonably used to increase the rate of fire of semi-automatic weapons as the possible rate of fire without Double Tap is already faster than some players are physically capable of firing. However if the player is physically capable of doing so it may be beneficial. It makes the W1200 much more effective and a hip fired submachine gun a serious close-range threat. Double Tap is tied perfectly with Stopping Power in terms of how fast an automatic weapon kills for guns that do 30 damage. Stopping Power wins out by hundredths of a second for automatic weapons that do more, and Double Tap wins by hundredths of a second for automatic weapons that do less. This perk does have significant drawbacks. It makes inaccurate and high rate of fire weapons hard to use at medium to long ranges. Effective hip firing may require the Steady Aim perk. You also will find yourself out of ammo very quickly and the Bandolier perk may be necessary.

Contrary to popular belief, Double Tap does have an effect on the M16A4, as it decreases the forced delay between bursts. Usually this delay reduces the average RPM of the M16 to a mere 350RPM, but Double Tap increases this by 135%.

Double Tap also affects the M1014. While it is indeed a semi-automatic weapon, there is a noticeable delay in how quickly each shot can be fired since it has a Rate of Fire of a mere 300RPM. Double Tap shortens this delay, allowing the M1014 to be fired extraordinarily fast. However, the M1014 only has a capacity of four shells, and the magazine will be exhausted in less than half a second if fired as quickly as other semi-automatics. It also effects the Winchester Model 1200 as it will lessen the time to pump the gun. This is true for the M1897 Trenchgun as well.

All semi-automatic rifles can benefit from this perk if the player has a fast trigger finger as all have a delay between shots. This will also give leniency to semi-automatics in Call of Duty 4 for their fire caps.

Double Tap also significantly increases a bolt-action rifle's ability to snipe against large groups of enemies, but Stopping Power is usually more beneficial because it is very hard to kill several enemies in a row without it due to the difficulty of aiming for one hit kill areas.

Trivia

 * Double tapping is a shooting technique in real life of squeezing the trigger of a weapon twice in quick succession to deliver two shots to the same target zone, though it is used only with semi-automatic fire, as fully automatic fire on most weapons already fires faster than any human can squeeze.


 * Double Tap is featured in the 3 zombie maps Verruckt, Shi No Numa, and the new map Der Riese as Double Tap Root Beer.