Chapter Relic: The Primarch's Wrath

Weapons with the Master-crafted special rule allow the bearer to re-roll one failed roll To Hit per turn with that weapon.

If a model has the Shred special rule, or is attacking with a Melee weapon that has the Shred special rule, it re-rolls failed To Wound rolls in close combat.

Similarly, if a model makes a shooting attack with a weapon that has the Shred special rule, it re-rolls its failed To Wound rolls.