This short guide what it is Gracing Shot skill and how it works.
Explanatory Guide to Gracing Shot Skill
Gracing Shot is useful if someone has very high piercing resistance but little to no slashing resistance. It’s situational at best.
It’s supposed to give a 50% damage buff too. But you need to upgrade the skill to have it give +50% damage.
Also Gracing Shot skill allows you to damage shields.