Nemesis bolter

"Attacks made with the Precision (X) Special Rule are allocated by the Attacking Player, not the Defender."
When any Hit Test is made for an attack with the Precision (X) Special Rule, if the result of the Dice roll, before any modifiers are applied, is equal to or great than the value of X attached to this variant of the Precision (X) Special Rule, then if a Hit is inflicted by that roll, that Hit becomes a 'Precision Hit'.

These Precision Hits must form a separate Fire Group or Strike Group. Wound Tests are made as normal for Precision Hits and cause Precision wounds. In Step 8 of the Shooting Attack process or Step 7 of the Initiative Step sequence, when selecting a Target Model for a Fire Group or Strike Group that is made up of Precision wounds, the Target Model is not selected using the normal Rules. Instead the attacking Player chooses which Model in the Target Unit will be the Target Model, and may select any Model that is a part of that Unit.

Note that Models Engaged in a Challenge cannot use this Special Rule to allocate Hits to any Model other than the enemy Model that is Engaged in the same Challenge and that any attacks which are made as Snap Shots, or for Weapons or attacks that have either the Blast (X) , Barrage (X), Template or Reaping Blow (X) Special Rules, may never trigger the Precision (X) Special Rule no matter what the result of the Hit Test is.

"Weapons and other attacks that have the Pinning (X) Special Rule have a chance of inflicting the Pinned Status on the Target Unit."
If a Shooting Attack made for a Weapon or Model with this Special Rule inflicts one or more wounds on a Target Unit, regardless of whether any Damage is inflicted, that Target Unit must make a Cool Check in the Morale Sub-Phase of the same Player Turn. If this Check is failed then all Models in the Unit gain the Pinned Status, if the Check is passed then there is no further effect. The value of the X attached to this Special Rule is applied as a negative modifier to the Cool Characteristic of Models in the Target Unit when making Checks caused by an attack with this Special Rule, if the attack includes multiple Weapons with different versions of this Special Rule the modifiers do not stack - use only the greatest modifier.

"With a Weapon that has a Breaching (X) Special Rule there is a chance that a Wound Test may result in the Wound ignoring Armour Saves."
When any Wound Test is made for an attack with the Breaching (X) Special Rule, if the result of the Dice roll, before any modifiers are applied, is equal to or greater than the value of X attached to this variant of the Breaching (X) Special Rule, then if a wound is inflicted by that Wound Test, that wound becomes a 'Breaching Wound'.

A Breaching Wound is always treated as having an AP of 2 regardless of the Characteristics of the Weapon used to make the attack.

"Weapons with the Heavy (X) Special Rule gain +1 to a Characteristic when Stationary."
When making a Shooting Attack with a Weapon that has the Heavy (X) Special Rule, a modifier of +1 is added to a Characteristic if the Model with that Weapon is part of a Unit that remained Stationary in the Controlling Player’s previous Movement Phase. If the Characteristic listed is AP, then instead it improves the AP by one Step. The value of X in the specific variant of the Heavy (X) Special Rule determines which Characteristic gains the +1 modifier.