5-8% Strength for 4.5s on Kill. Stacks 5 times.
Up to 5-20% Strength based on the charge time of your heavy attacks. Stacks 3 times.
14-20% Strength for 5s when every pellet in a shot hits the same enemy.
6-12% Critical Chance for each Enemy Hit by your previous attack. Stacks 5 times.