5-8% toughness on Chained Hit.
Hitting at least 3 enemies with an attack, increases your cleave by 140-200% for 2 seconds.
20-35% Toughness on Elite Kill.
5-8% Strength for every shot fired during continuous fire. Stacks 5 times.
I'm pretty sure this build sucks.
Edit: build is good at stagger and ammo wasting.