Armor & Ammo FAQ
Here are a couple of posts that I made on Interplay's Fallout message board
regarding the way ammo and armor statistics work in Fallout and Fallout 2. I
hope they help some of those wierd stats make more sense =)
Armor & Ammo Statistics: REVEALED!
Posted by HunterZ, hard-at-work on Sep 21, 1999 at 21:55:19:
Here's a bunch of info I've come up with (through research and reasoning)
regarding the way the Fallout/Fallout 2 game engine uses armor and ammo
statistics. The first (and longest) part of this post is going to be about
armor, and the second will be about ammo (as in bullets, etc., for guns) Note
that all of my comments (including the entire Ammo section) are only my best
guess as to how things work, so I may be a bit off here and there.
This is the section on Armor. Here I'll list some excerpts from the Fallout 1
manual (pages 5-12 and 5-13 - I chose the FO1 manual because it's more
detailed in regards to what I want to talk about), followed by my comments.
BTW, if you lost the manual to Fallout 1 or 2, there is a digitized copy on
your game CD in the MANUAL folder (in Adobe Acrobat format)
Fortunately, armor can protect against damage. Armor is a protective apparel
worn to defend against attacks and damage. Better armor can protect against
bigger attacks. There are three factors that determine the quality of armor.
ARMOR CLASS (AC): The first function of armor is to prevent the wearer from
being hit by the attack. This is known as Armor Class (or AC). The higher the
AC, the better the armor. The AC subtracts from the to hit chance of the
attacker. Example: you are wearing light leather armor, with an AC of 15%.
Your attacker has a base to hit chance of 50% (assuming all the other
modifiers have been taken into account). His final to hit chance is only
(50% - 15%) 35%." (FO1, p.[5-12]-[5-13])
Put simply, a character's armor makes them less likely to take ANY damage at
all. In other words, armor with a higher AC is more likely to cause a bullet
(or whatever) to bounce right off of you than to hit you and cause damage.
"DAMAGE THRESHOLD (DT): The second step is blocking the damaging energy of the
attack. This is known as the Damage Threshold (or DT). The DT is subtracted
from the hit point damage of the attack. Example: Assume the above attacker
succeeds. His attack does 20 points of damage (ouch!). You have a DT of 4. The
first four points of his attack are stopped, with only 16 (still ouch!)
getting through the first phase of your armor." (FO1, p.[5-13])
Basically, DT represents the amount of damage that an attack loses when it
penetrates the armor if it is determined that the attack IS going to do
penetrate the armor and do some damage to the target (i.e. the attack didn't
totally miss, and the armor didn't block ALL of the damage right off) For
example, if the armor's DT for Normal (melee/bullet) attacks is 2, the armor
is guaranteed to block 2 points of damage from Normal attacks if it fails to
block all of the damage.
Where do you find the DT of your armor? Well, when you bring up your inventory
screen, you'll notice in the upper-right corner that some stats on your armor
will be displayed. First is the AC, followed by a list of different types of
damage and how good your armor is at resisting them. This list will be
composed of elements like these:
" Normal: 4/50%"
The first number is the DT, and the second number is DR (explained below)
"DAMAGE RESISTANCE (DR): After the DT, the Damage Resistance (or DR) of your
armor takes over. This represents the ability of armor to slow down and
disperse the damaging energy. DR is expressed as a percentage. This is the
percent of the remaining damage that is nullified. Example: The 16 points from
the above attack are still coming. You have a DR of 20%. The damage is reduced
by (16 x .2) 3.2 points of damage (round down), or 3 points. The final attack
does only 13 points of damage, which is a heck of lot better than the initial
20 points." (FO1, p.[5-13])
DR is the percentage of the remaining damage which the armor will absorb as
the attack passes through the armor on its way to the actual target's body. It
looks complicated, but all that's really going on here is a subtraction of the
amount of damage (which is proportional to the amount of damage caused be the
attack because DR is a percentage) absorbed by the armor so that the final
amount of damage done to the target can be determined. DR is usually going to
prevent a lot more damage to a target than DT, since DT only stops a fixed
amount of damage, while DR stops more damage as the amount of damage inflicted
on the armor increases.
"Armor is always expressed as: Armor Class, DT/DR." (FO1, p.[5-13])
This is just pointing out a way to describe the protective abilities of a suit
of armor. Something interesting to note, however, is that it also lists the
stats in the order that they apply to an attack as it passes through the armor
to hit the target:
1. [AC] Attack hits outer layer of armor and may or may not be deflected.
2. [DT] Attack loses strength as a result of punching a hole in the armor.
3. [DR] Armor absorbs a certain percentage of attack's strength, depending on
the armor's ability to protect against that type of attack.
Once you understand how armor works in Fallout 1 & 2, ammo stats are pretty
simple. First off, if you examine a pile of bullets in your inventory, you
will see three (3) stats: "AC Mod", "DR Mod", and "Dmg Mod". Let's go over
them in detail:
AC MOD: This is the property of ammo that determines whether it will
counteract, enhance, or leave unchanged the AC of a target when determining
whether or not the bullet will hit the target. The AC Mod is a either a
positive or negative number (or zero), and is probably added to the target's
AC when determining whether or not the armor will completely deflect the
bullet. Therefore, ammo with a negative AC Mod (such as -35) is going to be
more likely to penetrate armor than ammo with a positive AC Mod (such as 10).
For some reason, the people who designed the Fallout 1 & 2 game engine decided
not to use different AC Mod vaules for Armor-Piercing [AP] ammo than they used
for normal (such as Jacketed Hollow-Point [JHP]) ammo, meaning that AP ammo
isn't any better at punching through high-AC armor than non-AP ammo. This is a
shame because it cuts the usefulness of AP ammo in half.
DR MOD: As you may have guessed, DR Mod is just like AC Mod, only it applies
to the Damage Resistance [DR] of the target's armor when determining how much
damage from an attack is absorbed by the target's armor. The DR Mod of ammo is
also a positive, negative, or zero number, just like AR Mod, and is also
(probably) added to the target's armor's DR Mod, just like with the ammo's AC
Mod. A suit of armor is able to absorb less damage from a bullet with a
negative DR Mod (such as -10) than from a bullet with a positive DR Mod (such
The reason I said earlier that Armor-Piercing [AP] ammo is half as useful as
it could be (as opposed to utterly useless) is that most AP ammo _does_ have a
lower DR Mod than most non-AP ammo of the same caliber. This basically means
that, while a 10mm AP round is going to be just as likely to bounce off of
armor as 10mm JHP, that same suit of armor isn't going to absorb as much of
the damage from the 10mm AP bullet as it would from a 10mm JHP round.
DMG MOD: This is the ammo stat that I'm least sure of, but my best guess is
that it's a fraction that determines how much more or less damage the ammo
does than the base damage range of the weapon that fires that ammo. Dmg Mod
values are usually expressed as fractions such as 1/2 (half damage), 1/1
(normal damage), and 2/1 (double damage).
Most guns which have both AP and non-AP ammo won't do the amount of damage you
think they will. Usually, the non-AP rounds for these guns do twice the guns
listed damage, while the AP rounds do HALF damage. This is because the shape
of AP bullets allows them to pass through armor more effectively (lower DR
Mod) while at the same time causing them to do less damage (smaller Dmg Mod)
when they actually hit their target. Non-AP bullets, on the other hand, are
designed to do maximum damage to the target (larger Dmg Mod), at the cost of
making it easier for armor to absorb more of the damage from them (higher DR
Mod). Therefore, if your attacks seem to be doing little or no damage to a
target, try using AP rounds instead; they'll do less damage than non-AP rounds
to a naked target, but if the non-AP rounds are getting deflected it's just
not worth it to worry about their higher damage potential.
Congratulations! You have passed the Vault-Tec course on Proper Usage of Armor
and Ammunition. Please use this information wisely - the life you save could
be your own!
And remember, don't drink glowing water!
Armor-Piercing [AP] Ammo Issues
Posted by HunterZ on Sep 22, 1999 at 07:33:35:
In Reply to: Ap Ammo posted by Mystic-X:The Unknown on Sep 22, 1999 at
Yes, most non-AP ammo does FOUR (4) times as much damage to a naked target as
AP ammo of the same caliber! And because AP ammo has just as hard a time
piercing armor (breaking the outer layer of the armor - not to be confused
with penetrating) as non-AP ammo, the only time AP ammo is worth using is when
someone is wearing armor that has such a high DR that it's sucking up all the
damage from a non-AP round until there isn't any left. If you want to see this
in action, try shooting the Vault City guards with an Assault Rifle loaded
with 5mm JHP rounds - it won't do any damage, even with point-blank bursts! If
you load it with 5mm AP rounds, however, it will actually do some damage
(although not very much - I'd suggest using the 5mm Assault Rifle for firewood
[but save the ammo])