Based on the statement "Each time this model is selected to shoot or fight, re-roll a Hit roll of 1 and re-roll a Wound roll of 1," the most common and logical interpretation is that the model would re-roll all rolls of 1 for both the Hit roll and the Wound roll each time it is selected to shoot or fight.
Here's the reasoning behind this interpretation:
- Consistency with other abilities: In Warhammer 40,000, many abilities that grant re-rolls typically allow for re-rolls on every instance of a specific roll result. For example, if an ability allows re-rolls of 1s to hit, it usually applies to all 1s rolled for hit rolls, not just once per phase.
- Balance and effectiveness: Allowing re-rolls for all 1s on both Hit and Wound rolls enhances the effectiveness of the model and provides a consistent advantage throughout the game. It improves the model's chances of successfully hitting and wounding targets, which can be valuable in combat.
- Clear wording: The statement "Each time this model is selected to shoot or fight, re-roll a Hit roll of 1 and re-roll a Wound roll of 1" does not specify any limitations on the number of re-rolls. It implies that the re-roll is applicable to any and all instances of rolling a 1 on Hit and Wound rolls.