Up to +5-20% Strength based on the charge time of your heavy attacks. Stacks 3 times.
+3.5-5% Strength for 3.5s on Hit. Stacks 5 times.
+5-8% Strength for every 10% of magazine spent during continuous fire. Stacks 5 times.
+1-4% Toughness for every 10% of magazine spent during continuous fire. Stacks 5 times.
66% Ammo is a breakpoint (19 ammo mag) on ripper guns to proc 10% mag spent blessings with each shot.
Headtaker -> Slaughterer or Headtaker + Slaughterer are completely viable.