Normal base damage multiplers.
Damage: [Serration]
Multishot: [Split Chamber] and [Vigilante Armaments]

Weapon is a Critical weapon.
Critical Chance: [Point Strike]
Critical Damage: [Vital Sense]
Critical Damage on Zoom: [Bladed Rounds]

Status Effects for Eidolons.
Eidolons are said to be best affected by Radiation damage.
Electricity: [Stormbringer]
[Hellfire]: Heat
These two can be changed out depending on your targets.

Build is discussed in video below.