A war machine engraved with a Rune of Penetration increases the Strength of its shots by 1, to a maximum of 10.

A war machine engraved with two Runes of Penetration increases the Strength of its shots by 1, to a maximum of 10, and allows the user to re-roll a single failed To Wound roll during the course of the battle. A third Rune of Penetration has no further effect.

Note that in the case of a Grudge Thrower, this bonus increases the Strength of both Strength values in its profile.