Up to 5-20% Strength based on the charge time of your heavy attacks. Stacks 3 times.
Hitting an enemy gives them 1-4 stacks of 2.5% Brittleness. Debuff lasts for 5 seconds and can have a maximum of 16 stacks.
5-8% Strength for every 10% of magazine spent during continuous fire. Stacks 5 times.
7-10% Strength for every 4 Single Target Hits. Lasts 2s and Stacks 5 times.