i wondered what would happen if you fire a big bad gun like lascannon and roll up 3 or more tens? roll rightous fury for each dice or?

Now that you mention it, the rules are a bit unclear about this, I was thinking that a weapon that does more than one d10 damage with just one shot won't benefit from more than one 10, but a weapon that is capable of semi- or full-auto can benefit from several 10s, simply because it is each bullet , not just each d10, that is capable of receiving Righteous Fury. I don't think it has ever come up in any of our sessions though.

Sarius said:

It's not an official ruling - the official rules aren't exactly clear on the matter, hence why this question keeps coming up - but I've got a house rule for this situation that's worked pretty well in the past.

Basically, when you roll one or more 10s for damage, roll to 'confirm' the righteous fury as normal. If this is successful, you roll the number of dice that scored 10 again - so if you only get a single 10, righteous fury gives you an extra 1d10 damage, but if three of the dice came up as 10, then you'd roll 3d10 extra damage.

Same for me. Only the dice that actually come up 10 get to be rerolled.

i've never thought the rules weren't clear.

Righteous Fury says that if you roll any 10's on your damage roll then you make your attack roll again and if that roll is successful then "You can roll AN ADDITIONAL 1d10 and add the result to the total. Should this additional DIE also be a 10,..." (Emphasis mine)

That seems pretty clear to me that no matter how many damage dice you roll or how many 10's you roll if you succeed with the second attack roll you roll one additional die. Weapons with multpile damage dice improve your chances of getting Righteous Fury but you still only roll one additional die for it.