Dakka

"A time shall come when lethal projectiles may transcend interdimensional barriers, when firepower shall occupy the entirety and eternity of space and time, and all of it fixed in an ever-abiding cycle as bullets, shells, lasers, flames, plasma bolts, and slugs are loosed infinitely from an utterly unbounded amount of automatic weaponry. The cosmos shall cease to exist, and reality itself shall be supplanted by a single, glorious cosmic cacophony of gunfire and muzzle flashes. Then, and only then, will there be enough dakka. Or at least almost." —The God-Emperor of Mankind, If The Emperor Had a Text to Speech Device, Episode 12, Season 3

DakkaDakkaDakkaDakkaDakkaDakkaDakkaDakkaDakkaDakkaDakkaDakkaDakkaDakkaDakkaDakkaDakka
You iz dead now ya stoopid 'umie! —Every Ork ever

Dakka is Ork slang for rapid fire capability and an onomatopoeia for the sound of automatic guns shooting. You need moar of it. No exceptions. Although other races need it too, when they use it, it's just not cool anymore. Must have something to do with that rockin' Ballistic Skill 2 that da Orks are throwing down. It is a widely corroborated scientific fact that you can NEVER have snuff dakka, because the only way that's possible is if you were to stretch an infinite plane of machine guns from one end of the observable universe to the other, and have them all firing on a bottomless magazine. And even then that's still not enuff dakka, because there are OTHER universes that still need dakka.

Several other non-Orky races in Warhammer 40,000 have at least one weapon that relies on sheer dakka to be effective.

Imperium: Multilasers, Hellguns, Leman Russ Punisher, Lasguns, Laspistols, Heavy Bolters, Storm Bolters, Assault Cannons, Combi-bolters, Autocannons, Vulcan Megabolters, Psycannons, Heavy Stubbers.
Chaos: Harvester Guns, Mawcannons, Butcher Cannons, Storm Lasers, Reaper Auto-cannons,Hades Auto-cannons, Autoguns, Autopistols, Heavy Stubbers, Shotguns, Heavy Bolters
Eldar: Scatter Lasers, Shuriken Catapults, Shuriken Cannon.
Tau: Burst Cannons, Cyclic Ion Guns, and to a lesser extent Ion Cannons
Necron: Gauss Cannons, Gauss Blasters, and Tesla Destructors.
Tyranid: Devourers, Biocannons, Deathspitters.

Too Much Dakka

It's actually possible to get too much dakka. In Dawn of War 2, if you pin down some Orks with enough firepower they will shout "WAAAH! Too much dakka!" There's too much dakka when it's being fired at you *BLAMBLAMBLAMBLAMBLAM* HERE...HURR...UM, YOU IS SAYIN' BAD T'INGS WOT YOU SHOULDN'T SAY!

Examples of maximum dakka (but not enough)

Tyranids:

HQ:

2x hive tyrant w/ 2 brain-leech worms

Elites

3x 3 hive guard w/ impaler cannon

Troops

6x 30 Devilguants

Fast attack

3x 30 gargoyles w/ fleshborers

Heavy support

3x 3 carnifex w/ 2 brainleech worms

Total dakka: 780 shots per turn

YOUZ CHOMPY GITZ SEZ THAT'S DAKKA?

Astra Militarum (Imperial Guard)

HQ: Company Command Squad

Troops:

6x Platoon Command Squad

6x5 Infantry Squad

6x Conscripts Squad

6x5 Heavy Weapons Team w/ Heavy Bolters

Heavy Support: 3x3 Leman Russ Punisher w/ Heavy Bolter sponsons

Total dakka: 949, 1549 on close range or w/ orders, 2149 per turn on close range and orders. And it's without getting full platoons or even FOC. Because that would be just insane.

(but maybe enuff dakka)

"And if that don't work, use more gun."- The Engineer