I feel somewhat silly asking this, but the Wild Talents 2E rulebook keeps likening heavy armor to a "really thick eggshell" that is "all or nothing." I was under the impression for quite a while that Heavy Armor and Interfering Defends powers really were all-or-nothing. For example, I thought that if someone had 5 heavy armor, and an attack of width 5 hit it, nothing would get through, but if an attack of width 7 hit it, the person wearing the armor would take the full seven damage. Reading through again, however, I can't find anything to support this, so it makes me think that a person wearing heavy armor 5 hit with an attack of width 7 would take 2 damage. Which interpretation is correct?
In Wild Talents, there are two flavors of armor. Light Armor (LAR) and Heavy Armor (HAR).
Light Armor does two things. First it reduces all Shock damage from the attack to 1. Then it transforms a number of killing damage from the attack equivalent to its rating to shock. The remainder is taken as killing damage.
For example, if you have LAR 3, and get hit with an attack that does 6 shock and 6 killing, you'd take a grand 1 shock from the 6 shock, then 3 more from the LAR 3 converting 3 of the killing to shock for a total of 4 shock. Then you'd also take the remainder killing for 3 killing.
Heavy Armor is a bit different. Heavy armor reduces the width of the attack roll before damage is figured. The fact that it reduces width is where the "all-or-nothing" designation comes in. If the width is reduced to 0 or less, you do no damage. But if the width is greater than 0 after the HAR is taken into account, you add the pluses from the damage, and they are not reduced at all.
So, if you have HAR 2, and get hit with an attack from a machine gun that does W+2K, and the roll is Width 2, the +2 doesn't matter. The attack is reduced to Width 0, and doesn't make it through. If the roll is Width 3, only one point gets through- but all of the pluses count at full strength, unreduced by the armor.
So, the short of it is, you're right, the damage is reduced by the armor. But it's the Width that is reduced- not the final damage.
As I am looking for the answer to the very same question, I found this post, from 10 months ago, yes, but the answer provided is wrong (at least for my version of the game, Essential Edition), so I will add my few cents.
HAR blocks any attack that after reduction is not minimum of two width:
What confuses me is that the damage formula includes width, while the HAR does reduce it, the description states, that it does not reduce damage, only width. So... it reduces it, but does not reduce.
It is unclear whether you should include the reduced or unchanged width into the damage. There are even more confusing info further, like:
How am I supposed to interpret this? Nearly does not equal full, while reduced width is far from "nearly full damage", especially considering higher numbers, like 3 HAR. Of course, when we are talking about ballistic missiles, the bonus damage is hight enough to wreck whatever is on the other side of that HAR, but without flat bonuses, like punching with hero of 7 Body attribute (Lethal Damage), it is important whether something with 3 HAR takes two damage or five.
Later on we have penetration:
This is only bringing more confusion, does the penetration negates damage reduction from HAR, or does the quoted description repeats some cryptic information from HAR description?
I mean, it states, that if the armor is pierced, it makes the attack inflict full damage, like it's some special function of pierce. The last part doesn't even make sense, of course if the attack does not manage to pierce HAR, it does not deal damage... it's considered as a miss in game's mechanic, no width = no hit.
So, after this analysis, I would say, make it however pleases you, I will be rolling with simple damage reduction, maybe even allow width 3 rolls to hit for one width HAR of 2. And of course, arbitrarily not allowing certain forms of attacks to pass HAR at all, like simple gunfire.