Up to 5-20% Strength based on the charge time of your heavy attacks. Stacks 3 times.
7.5-15% Weak Spot Damage. Weakspot Kills also ignore Enemy Hit Mass.
Killing an enemy by firing both barrels makes your next Reload 40-70% faster.
6-12% Critical Chance for each Enemy Hit by your previous attack. Stacks 5 times.