Effective Efficiency = 50% more ammo or 50% more heat capacity for your weapon

Blessing of St. Victorious limits max damage for single hit to 30%, gives you time to run away.

Cull the Weak adds 50% damage to any enemies affected by debuff, helps clear out hordes, esp. if you have stuff that enhances damage, like fire -> burn, adds stun, adds shock, and so on. Remember I am also running "fire aura", so anything that adds fire -> burn or heat damage, is great.