Hitting at least 3 enemies with an attack, increases your damage by 24-36% for 3 seconds.
+35-50% Cleave on Hit. Stacks 5 times.
+70-100% Critical Weak Spot Damage.
+14-20 Critical Chance on Weak Spot Hit until your next Critical Hit. Stacks 5 times.
The vigilant autogun takes a bit to get used to but once you get used to it and add the fact that the zealot can maintain close to 100% crit with it, and suddenly it sings.