Iliastus Assault Cannon

If a weapon with this special rule is used to make a Shooting Attack as part of any Reaction, it gains the Gets Hot special rule for that Shooting Attack.

If a model has the Rending special rule, or is attacking with a Melee weapon that has the Rending special rule, there is a chance that their close combat attacks will strike a critical blow. For each To Wound roll equal to or higher than the value listed, the target automatically suffers a Wound, regardless of its Toughness. The controlling player may choose to resolve these Wounds at AP 2 instead of the weapon’s normal AP value.
Similarly, if a model makes a Shooting Attack with a weapon that has the Rending special rule, a To Wound roll of equal to or greater than the listed value wounds automatically, regardless of Toughness, and is resolved at AP 2.
In either case, against Vehicles each Armour Penetration roll of equal to or greater than the listed value allows a further D3 to be rolled, with the result added to the total Strength of the attack. These Hits are not resolved at AP 2, but are instead resolved using the weapon’s AP value.
For example, a model with the Rending (5+) special rule that rolls To Wound against a non-Vehicle model will wound automatically on the roll of a 5+, and the attacking player has the choice of using an AP value of 2 instead of the AP value of their weapon.

When firing a weapon that Gets Hot. roll To Hit as normal. For each unmodified To Hit roll of 1, the firing model immediately suffers a single Wound with an AP value equal to that of the weapon that was used to attack (Armour Saves, Invulnerable Saves and Feel No Pain rolls can be taken, but not Cover Saves or Shrouded rolls) - this Wound cannot be allocated to any other model in the unit. A Vehicle instead rolls a D6 for each roll of a 1 To Hit. If this roll results in a 1 or 2, the Vehicle suffers a Glancing Hit.

Gets Hot and Weapons that do not Roll To Hit 
Weapons that do not roll To Hit (such as Blast weapons) must roll a D6 for each shot immediately before firing. On a 2+, the shot is resolved as normal. For each roll of a 1, the weapon Gets Hot; that shot is not fired and the firing model immediately suffers a single Wound with an AP value equal to that of the weapon that was used to attack (Armour Saves, Invulnerable Saves and Feel No Pain rolls can be taken, but not Cover Saves or Shrouded rolls) – this Wound cannot be allocated to any other model in the unit. A Vehicle instead rolls a D6 for each roll of a 1 to Hit. If this roll results in a 1 or 2, the Vehicle suffers a Glancing Hit.

Gets Hot and Re-rolls
If a model has the ability to re-roll its rolls To Hit (including because of BS 6+ or the Twin-linked special rule), a Wound is only suffered if the To Hit re-roll is a 1; it may also re-roll Gets Hot results of 1 for weapons that do not roll To Hit.

When attacking with a weapon that has this special rule, the controlling player may re-roll all failed To Hit rolls.

Twin-linked Blast Weapons
If the Scatter dice does not roll a Hit, you can choose to re-roll the dice when making a Shooting Attack with a Twin-linked Blast weapon. If you choose to do so, you must re-roll both the 2D6 and the Scatter dice.

Twin-linked Template Weapons
Twin-linked Template weapons are fired just like a single weapon, but must re-roll failed To Wound rolls and Armour Penetration rolls.