Zapp & Roger
 Skitarii Build - Warhammer 40k: Darktide 

To maximize Zapp, AS > Cleave > Crit.

AS and Cleave helps both charge spending & charge building (more enemies hit -> quicker charge generation -> more Zapp).
Crit is mainly to proc Electro-Strike Conduit and the goodies on top of the talent tree.

• Horde/mixed: push every ~4s (push -> light-> heavy -> heavy is the reliable way to get to horizontal swings). Maul generates 1 Zapp charge per enemy hit, that's why you wanna cleave as much as you can.
• Single target: zapp increases single target damage. ~241 on flak/carapace, ~216 on unarmored, ~192 on infested/unyielding - and it can crit too! That means in a clutch activating arc + spamming lights will have great dps even against the most armored enemies. Against a bunch of hard targets the more efficient way is the proper heavy->light overhead loop, but hey, it's good to know that when things gets real messy, activating arc + spamming light can be enough to kill some elites, regain a charge of Voltaic Emitter, and keep it going.
• Activate Zapp often, for real, it'll come back soon enough

Blessings

/e After playing it for a while, Voltagheist Overload was a bit underwhelming compared to the always-active blessings.

Hammerblow feels nice with the already good stagger values of this weapon. The huge stagger makes me feel safe enough to drop some defensive talents, so it's win/win.

Ranged

Ranged is flex. 

• Phosphor pistol is quick to draw, great to snipe specials + great against bosses - overall an awesome weapon
• Arc Rifle have outstanding ammo economy, allows ranged debuff of dangerous enemies (bosses & crusher packs) and is more thematic, at the cost of being slower to draw & to reload. If you go with it, swap Superior Defence Engrams & Hybrid Combat Covenant for System Shock & Capacitor Reclamation Loop 

In the end, as long as you're able to handle specials/gunners in a pinch, every gun is fine, so you should really pick your favorite.