User blog comment:Neppudere/Time to lay down the LAW: Legendary Archwitch Guide/@comment-13020706-20150925102211

There is a pretty logical reason why you cannot deal over ~3.2m (~4.2 m for opposing element) from just tapping with a bursted GUR.

It's NOT the damage that is capped. It is a game mechanic that the ATK value has a hard cap. A card cannot exceed ~4 million ATK (my estimate) regardless of how many buffs it receive. Here are the reasons why I think this:

1) If the cap is on damage, the amount of damage would be consistent. Since it is not consistent, the cap is definitely on ATK because the damage that results from a given value of ATK is always somewhat random.

2) In general, when a card has very few soldiers remaining (e.g. 1% of max soldiers), the effect of dealing reduced damage is apparent regardless of how many buffs it has received. It will deal considerably less than 999,999 damage the closer the card is to dying. The only explanation for this is that ATK is capped.

I haven't tried myself, but in theory, a card with an ability that has a damage multiplier should be able to exceed ~3.2m damage when bursted. This means a bursted GSR/GUR critter can crit for ~32m damage (or ~42m) with a lot of buffs. Also, cards with Witch Hunt should have their tap attack multiplied accordingly. Can anyone confirm?