Mass Effect 2: Gameplay data (by BioWare developers)

The information in this post was originally provided by Eric Fagnan.


Ammo Powers:
Ammo powers make a single, separate damage call before the initial weapon damage call, and they use their own damage multipliers on resistances and health, as Christina mentions above.

Example:
If the initial regular weapon damage is 100 against a target with shields, then:
With Disruptor Ammo rank 1, you do an additional 20 damage to shields. If any of this damage passes through to health, it is negated (unless hitting a synthetic enemy) since this ammo power does nothing to health.
With Incendiary Ammo rank 1, you do no extra damage since this ammo type does nothing to shields.

Because the ammo power does the damage call before the weapon does its regular damage, using an ammo power against the wrong resistance type can totally negate its damage. For example, if you use Armor Piercing Ammo or Incendiary Ammo against an enemy that has a single point of energy shields, your ammo power's damage will have no effect, even though your weapon's regular damage will take down the shields afterward. Ammo powers do not make 2 damage calls.

If the ammo power does go through the first resistance, like Armor Piercing Ammo hitting armor, and there is damage left, it passes through to the next defense.

Additional effects like Disruptor Ammo's "stun robots" or "overheat weapons" only apply if the target no longer has resistances. So even if you are using Disruptor Ammo against energy shields, the shields must be completely off before the target can be stunned or overheated.

Ammo Powers benefit from + Power Damage bonuses, such as the +15% power damage from the Blood Dragon armor. However, they do not get benefits from + Biotic or Tech bonuses or any other bonuses specific to certain types of powers. Only the caster's power damage bonuses apply to the power. This means that when you cast a squad ammo power, the player's damage bonuses get applied to the ammo power on the henchmen, but not the henchmen power damage bonuses. This matters for henchmen like Garrus who has a passive power damage bonus. Similarly, when henchmen cast squad ammo powers on you, your damage bonuses do not apply.


Incendiary Ammo:
Each bullet impact from Incendiary Ammo adds a damage-over-time effect on the target that stacks, so you can have many of these on one target all doing damage simultaneously. However, if the target has resistances the damage is done instantly.


Warp Ammo:
Warp ammo does double damage to targets affected by biotics. What this means is that the extra damage from Warp Ammo is doubled, not the entire damage from the weapon + Warp ammo.

So if a normal shot from a weapon does 100 damage, then a rank 1 Warp ammo will do 15 bonus damage for a total of 115 damage. Against targets affected by biotics, the bonus damage is doubled to 30 for a total of 130 damage.

Warp ammo, like all other ammo powers, uses the weapon's base damage to calculate the bonus. They never take any weapon bonuses into account, so it doesn't get more damage from a target who is in ragdoll (see below for weapon bonus damage to ragdolled targets).

Another way to look at it is that against targets affected by biotics, Warp ammo increases weapon damage by 30%/50%/70%/100% for ranks 1/2/3 and the heavy evolved. In this case, it is the highest damage increase for weapon powers, but it requires an extra step for you to use a biotic on the target.

The information in this post was originally provided by Eric Fagnan.


General Combat:

Ragdoll/Frozen Weapon Damage Bonus:
All enemies take 100% more damage from regular weapons while frozen or in ragdoll. You have to wait until the enemy is completely frozen before getting this bonus, which usually takes only a couple seconds.

This also means that enemies ragdolled by biotics or other powers take more damage from regular weapons.

Melee:
Player melee attacks have a base damage of 125.

The Heavy Muscle Weave equipment increases melee damage by 25%.