On
the subject of stopping power
Warning: the following essay deals with a controversial subject,
and ultimately takes one side in the debate. This should not be
taken as an authority, but is included in order to lay a basis for
the game mechanics which follow.
Much has been written on the subject of the mechanics of gunshot
wound injury and the relative effectiveness of different calibres
and types of ammunition. Many gun journalists expound the theory
that kinetic energy (KE) is the key to 'stopping power', and that a
rapidly expanding or fragmenting bullet is necessary to ensure all
that energy is transferred to the victim and that the round does not
'over-penetrate' and exit the body.
Other (or often the same) writers believe that the large temporary
cavity created by bullets impacting at supersonic velocities
destroys tissue, or creates a 'hydrostatic' shock wave inside the
victim's body which can rupture blood vessels and organs, stop the
heart and injure the brain at distances far removed from the actual
wound.
'Hydrostatic shock' should not be confused with physiological or
psychological shock, which are well-understood processes.
Both
kinds of pundit apparently believe that traditional low-velocity,
round-nosed bullets which pass right through the human body, of the
kind which killed hundreds of thousands of people in the wars of the
19th
and 20th
centuries, are ineffective to the point where being shot with one
probably wouldn't even hurt that much.
These theories have become quite popular, but there are problems
with both.
The speed freaks' hydrostatic shock theory has very little solid
evidence behind it, and is mostly based on anecdotal accounts of
game animals instantly dropping dead when shot with very high
velocity rifle rounds. There are several problems with this.
One is that the accounts are anecdotal and subjective, and not the
result of scientific research. We simply don't know what proportion
of animals mortally wounded with high-velocity rifles collapse
immediately, and what proportion run for a distance before dying.
Another problem is that we don't know, nor will we ever, whether the
animals collapsed because of physiological shock, sudden massive
blood loss, or because they were knocked out by a 'hydrostatic
shock' to the brain.
Ultimately, hydrostatic shock ceases to hold water when one
considers that human (and animal) tissue is very tough and elastic,
and can survive hard impacts, squeezing and stretching with few or
no lasting effects. If a rapid change in pressure could burst our
arteries, it would happen every time our hearts beat.
However, it should be noted that higher-velocity bullets create a
wider permanent wound cavity than lower-velocity ones of the same
calibre, as the narrow area of very high pressure in front of the
slug crushes tissue (and crushing is the action of a bullet on
flesh).
Proponents of the KE transfer idea go as far as to say that shot
placement (where the bullet hits) matters not – except where the
brain and spinal cord is concerned – and that a magic number of
700 joules (500 foot-pounds) of energy, delivered to any part of the
body, will 'stop' or incapacitate the victim. By this token, a
hollow point bullet which embeds itself in the fatty tissue of an
obese man's paunch is more effective than a full metal jacket slug
which passes right through his torso and comes out his back.
However, much of the KE of a quickly-mushrooming bullet is not
transferred to the victim at all, but rather used to change the
shape of the projectile.
Furthermore, small arms simply don't have that much KE. A 7.62mm
NATO calibre rifle bullet has a kinetic energy of about 3,500 joules
at muzzle velocity. A one-ton car travelling at 10 miles per hour
has a KE of 12,500 joules – three and a half times as much – but
a hit from the former is much more likely to kill you than a hit
from the latter. Similarly, a blow from a police officer's truncheon
has more KE than a shot from their handgun.
Kinetic energy is a good way of comparing like with like. The
difference in KE between two firearm rounds or two vehicle impacts
is a good indicator of their lethality and destructive potential.
However, it is not the kinetic energy that kills you, it is the
nature of the work that energy does to your body that counts.
Despite what you might have read, bullets (like cutting and trusting
weapons) injure and kill by making deep, narrow holes in the human
body. The severity of the wound is mainly a question of where the
bullet hits (which internal organs are in its path), how deeply it
penetrates and how wide a hole it makes. Higher-velocity and
higher-calibre bullets are more effective because they make a deeper
and wider hole.
'Over-penetration' is not so much a problem, but rather a desirable
effect. A bullet that passes right through its victim, leaving a
large exit wound, will have more chance of hitting a vital organ
than one which comes to rest within the body. Taking into
consideration that one may need to shoot through a car door, tree
trunk or sandbag wall to hit one's intended victim, we can conclude
that the more penetration a weapon has, the better.
The truth is that there are no mysterious physics of wounding, nor
can it be boiled down to a mathematical formula. A person shot
through the heart or a major blood vessel will pass out from blood
loss in less than 15 seconds, and die not long after. A person shot
through their thigh muscle might fall over and pass out, or they
might not, but they're not going to die of that wound unless it goes
untreated and they get gangrene. In science the simplest answer is
not always the correct one, but in this case it is.
Firearms are very efficient weapons, much more so than weapons that
work by brute kinetic energy alone such as clubs or bombs. A bullet
propelled by the tiny amount of explosive in a rifle cartridge has a
greater lethal range than a low-yield nuclear weapon.
Firearms
have been in use since the 12th
century (in China) and have, when combined with the bayonet, been
the universal infantry weapon since the 18th
century. There are good reasons for this. The flintlock musket gave
the common peasant or urban labourer the ability to shoot the
steel-plated knight off his horse, rendering body armour obsolete
until the late 20th
century. The percussion rifles of the mid-19th
century could shoot a lead bullet right through one soldier's body
with enough force remaining to kill the man standing behind him.
Modern automatic weapons, although largely unchanged since the end
of WWII, have many times the fire power, accuracy and range of the
first cartridge arms.
In
Lead and Chrome, the wounding potential or Damage Class (DC) of
different firearms is calculated using a modified version of the
formulae developed by author and firearms expert Kevin Dockery in
his book Edge of the
Sword Volume One: Compendium of Modern Firearms.
Edge of the Sword
was apparently meant to be a fully-fledged role-playing system, but
it never materialised. What the book did contain was a combat
system, with formulae to calculate both the penetration of a firearm
and the total volume of the wound it creates.
In Lead and Chrome, the results of these formulae are 'crunched'
into the PEN and DC numbers. PEN and DC for non-firearms is
calculated based on the author's subjective judgements about their
likely effectiveness, based where possible on scholarly articles.
Hit
Location
Once a character has been shot, stabbed, punched or whatever, we
need to find out where they have been hurt. For this we use the hit
location table:
Primary Hit
Location Additional Hit Locations (for shotguns etc.)
Roll
D20: Roll D6:
1: Skull 1-6:
face and neck
2: Face
and neck 1-3: skull; 4-6: chest
3-4: Chest 1:
face/neck; 2: upper R arm; 3: upper L arm, 4: heart; 5-6: abdomen
5: Heart 1-3:
chest; 4-6: abdomen
6-8: Abdomen 1-3:
chest; 3: heart; 5: upper right leg; 6: upper left leg
9: Upper
right arm 1-3: chest; 4-6: lower right arm
10: Lower
R arm/hand* 1-3: upper right arm; 4-6: abdomen
11: Upper
left arm 1-3: chest; 4-6: lower left arm
12: lower
left arm/hand* 1-3: upper left arm; 4-6: abdomen
13-14: Upper
right leg 1-2: abdomen; 3-4: upper left leg; 5-6: lower right leg
15: Lower
right leg 1-3: upper right leg; 4-6: right foot
16: Right
foot 1-6: lower right leg
17-18: Upper
left leg 1-2: abdomen; 3-4: upper right leg; 5-6: lower left leg
19: Lower
left leg 1-3: upper left leg; 4-6: left foot
20: Left
foot 1-6: lower left leg
*For
lower arm/hand roll a D6: on a 1-4 the forearm is hit, on a 5-6 the
hand is hit.
Once we have determined location, we need to work out how seriously
the character has been hurt. For this we refer to the wound table on
the next page.
Attacks and the wounds they cause are divided into two categories:
Lethal and non-lethal.
There are five kinds of lethal wound: Scratch (SC) Flesh Wound (FW),
Crippling Wound (CW), Mortal Wound (MW) and Death/Amputation (DA);
and four kinds of non-lethal wound: Stinging (ST), Bruised (BR),
Stunned (ST) and Knocked Out (KO).
To determine what kind of wound a successful attack causes, roll
D10, add or subtract the relevant modifiers, and find the result in
the row corresponding to the attack's DC on the wound table.
Wound/damage roll
modifiers:
Range:
At every fourth range
band beyond Close (V Long and V Distant): -1 to Damage Class
Penetration vs.
Armour:
PEN less than AV: Zero
penetration
If
DC > than AV, attack causes a non-lethal wound at DC minus AV
PEN equals AV: Low
penetration
Attack
penetrates with -4 modifier to wound roll
Pen greater than
AV: Full penetration
Attack
penetrates with no modifier to wound roll
Target Size: Wound
Modifier:
1 +3
2 +2
3-4 +1
5-7 0
8-9 -1
10 -2
11-12 -3
13-14 -4
15-16 -5
17-18 -6
19-20 -7
21-22 -8
23-24
etc. -9 etc.
For melee attacks
only:
Attacker
Strength: DC:
1 -3
2 -2
3-4 -1
5-7 0
8-9 +1
10 +2
11-12 +3
13-14 +4
15-16 +5
17-18 +6
19-20 +7
21-22 +8
23-24
etc. +9 etc.
Location: Wound
Modifier:
Upper
limb: -2/-1 vs cutting weapons
Lower
limb: -1/0 vs cutting weapons
Hand
or foot: -1/+1 vs cutting weapons
Abdomen: +1
Chest: +2
Heart: +5
Face/neck: +2
Skull: +5
Previous wound state
at location:
FW/BR: +1
CW/ST: +2
MW/KO: +3
|
|
D10 Roll
|
|
1
|
2
|
3
|
4
|
5
|
6
|
7
|
8
|
9
|
10
|
|
Damage Class
|
⅙
|
SC/SG
|
SC/SG
|
SC/SG
|
SC/SG
|
SC/SG
|
FW/BR
|
FW/BR
|
FW/BR
|
FW/BR
|
CW/ST
|
|
⅓
|
SC/SG
|
SC/SG
|
SC/SG
|
SC/SG
|
FW/BR
|
FW/BR
|
FW/BR
|
FW/BR
|
CW/ST
|
CW/ST
|
|
½
|
SC/SG
|
SC/SG
|
SC/SG
|
FW/BR
|
FW/BR
|
FW/BR
|
FW/BR
|
CW/ST
|
CW/ST
|
CW/ST
|
|
1
|
SC/SG
|
SC/SG
|
FW/BR
|
FW/BR
|
FW/BR
|
FW/BR
|
CW/ST
|
CW/ST
|
CW/ST
|
CW/ST
|
|
2
|
SC/SG
|
FW/BR
|
FW/BR
|
FW/BR
|
FW/BR
|
CW/ST
|
CW/ST
|
CW/ST
|
CW/ST
|
MW/KO
|
|
3
|
FW/BR
|
FW/BR
|
FW/BR
|
FW/BR
|
CW/ST
|
CW/ST
|
CW/ST
|
CW/ST
|
MW/KO
|
MW/KO
|
|
4
|
FW/BR
|
FW/BR
|
FW/BR
|
CW/ST
|
CW/ST
|
CW/ST
|
CW/ST
|
MW/KO
|
MW/KO
|
MW/KO
|
|
5
|
FW/BR
|
FW/BR
|
CW/ST
|
CW/ST
|
CW/ST
|
CW/ST
|
MW/KO
|
MW/KO
|
MW/KO
|
MW/KO
|
|
6
|
FW/BR
|
CW/ST
|
CW/ST
|
CW/ST
|
CW/ST
|
MW/KO
|
MW/KO
|
MW/KO
|
MW/KO
|
DA/CW
|
|
7
|
CW/ST
|
CW/ST
|
CW/ST
|
CW/ST
|
MW/KO
|
MW/KO
|
MW/KO
|
MW/KO
|
DA/CW
|
DA/CW
|
|
8
|
CW/ST
|
CW/ST
|
CW/ST
|
MW/KO
|
MW/KO
|
MW/KO
|
MW/KO
|
DA/CW
|
DA/CW
|
DA/CW
|
|
9
|
CW/ST
|
CW/ST
|
MW/KO
|
MW/KO
|
MW/KO
|
MW/KO
|
DA/CW
|
DA/CW
|
DA/CW
|
DA/CW
|
|
10
|
CW/ST
|
MW/KO
|
MW/KO
|
MW/KO
|
MW/KO
|
DA/CW
|
DA/CW
|
DA/CW
|
DA/CW
|
DA/MW
|
|
11
|
MW/KO
|
MW/KO
|
MW/KO
|
MW/KO
|
DA/CW
|
DA/CW
|
DA/CW
|
DA/CW
|
DA/MW
|
DA/MW
|
|
12
|
MW/KO
|
MW/KO
|
MW/KO
|
DA/CW
|
DA/CW
|
DA/CW
|
DA/CW
|
DA/MW
|
DA/MW
|
DA/MW
|
|
13
|
MW/KO
|
MW/KO
|
DA/CW
|
DA/CW
|
DA/CW
|
DA/CW
|
DA/MW
|
DA/MW
|
DA/MW
|
DA/MW
|
|
14
|
MW/KO
|
DA/CW
|
DA/CW
|
DA/CW
|
DA/CW
|
DA/MW
|
DA/MW
|
DA/MW
|
DA/MW
|
DA/DA
|
|
15
|
DA/CW
|
DA/CW
|
DA/CW
|
DA/CW
|
DA/MW
|
DA/MW
|
DA/MW
|
DA/MW
|
DA/DA
|
DA/DA
|
|
16
|
DA/CW
|
DA/CW
|
DA/CW
|
DA/MW
|
DA/MW
|
DA/MW
|
DA/MW
|
DA/DA
|
DA/DA
|
DA/DA
|
|
17
|
DA/CW
|
DA/CW
|
DA/MW
|
DA/MW
|
DA/MW
|
DA/MW
|
DA/DA
|
DA/DA
|
DA/DA
|
DA/DA
|
|
18
|
DA/CW
|
DA/MW
|
DA/MW
|
DA/MW
|
DA/MW
|
DA/DA
|
DA/DA
|
DA/DA
|
DA/DA
|
DA/DA
|
|
19
|
DA/MW
|
DA/MW
|
DA/MW
|
DA/MW
|
DA/DA
|
DA/DA
|
DA/DA
|
DA/DA
|
DA/DA
|
DA/DA
|
|
20
|
DA/MW
|
DA/MW
|
DA/MW
|
DA/DA
|
DA/DA
|
DA/DA
|
DA/DA
|
DA/DA
|
DA/DA
|
DA/DA
|
How to use the
wound table
First, total up all the positive and negative wound modifiers (for
location, target Size, ammunition type and so on) Find the the
attack's DC in the left-hand column. Roll D10 and count across the
horizontal row for the DC to the corresponding box.
Next, apply the wound modifier: for positive modifiers (+1, +2 etc.)
shift the result one column to the right. If you reach the
right-hand edge of the table with point to spare, start moving down
the rows instead. For negative modifiers (-1, -2 etc.), shift the
result one column to the left. If you reach the left-hand edge of
the table with points to spare, start moving up the rows.
Wound
state definitions and effects
Lethal
wounds:
Scratch
(SC)
A Scratch bleeds and hurts a little (although the character may not
even notice in the heat of battle). This does affect the character
physically in any appreciable way, but they still have to make a
Nerve check for being hit.
Flesh
Wound (FW): A Flesh Wound is
more than just a superficial scratch, but it is neither
life-threatening nor greatly debilitating. It will bleed enough to
leave drops and smears of blood on the ground and in other places,
which other characters and some animals (sharks for instance) can
track.
A character suffering a Flesh Wound must make a D10 roll equal to or
less than their Nerve with a -3 die modifier, or pass out from pain
and shock (effectively stunned: see non-lethal damage below).
Actions with the wounded location are made at a cumulative -1
modifier to the relevant character statistic for every flesh wound
suffered.
Some examples of wound effects are as follows:
Arm
or hand: -1 to Dexterity,
Strength and Tech skills per FW for tasks to that arm.
Leg
or foot: -1 to Agility and
Strength skills per FW to that leg.
Face/Neck:
-1 to Intelligence, Appearance and Empathy-based skills per FW.
Skull:
-1 to Intelligence, Appearance and Empathy-based skills per FW, plus
a 25 per cent chance that blood will flow down into the eyes,
partially blinding the character.
Flesh wounds take one week to heal with an easy Medicine or average
First Aid check.
Crippling
Wound (CW): A Crippling Wound
indicates a broken bone or severely lacerated major muscle, which
renders the location useless until healed. A Crippling Wound is not
life-threatening, but the character must roll equal to or under their
Nerve with no modifier, or pass out (as with a Flesh Wound). It may
bleed a lot and leave an easy-to-follow trail of blood.
Arm
or hand: The character drops
anything held in that hand and cannot pick up or manipulate anything.
Leg
or foot: The character cannot
walk and must make a Difficult Athletics roll to remain standing.
They can move by hopping (⅓
walking speed) or using crutches (½
walking speed), furniture or scenery for support (⅓
walking speed), or by crawling (⅕
walking speed). The
character can also climb at a -3 task modifier. If both legs are
affected at once the character automatically collapses, unless
already seated or lying.
Abdomen:
The character cannot run and can only walk at ⅓
normal speed.
Chest:
The same effects as a CW to the abdomen, plus the character suffers a
-3 modifier per CW to all tasks due to shortness of breath and
accompanying dizziness.
Face/Neck:
The character cannot speak and
has difficulty breathing, giving a
Skull:
The wound renders the character unconscious (most likely with a skull
fracture) until they have recovered to FW status.
Mortal
Wound (MW): A major blood
vessel or vital organ (such as a lung or the trachea) has been
severed or badly damaged, and the character is bleeding or
suffocating to death.
The wounded character must make an immediate Nerve -3 roll to remain
conscious, and must then roll under their Constitution/Toughness
every round to stay alive, with a cumulative +1 modifier to the roll
every round after the first. They must keep rolling until they die or
until the wound is stabilised. A natural roll of a one indicates that
the wound has staunched by itself and the character is out of
immediate danger. A Mortal Wound can be stabilised by another
character on a successful Difficult Medicine or Very Difficult First
Aid task, but if the character has more than one mortal wound, each
must be treated separately.
Death/Amputation
(DA): This is a wound which
instantly kills the character beyond any hope of being saved through
medical treatment, or which amputates a limb. Effects by location are
as follows:
Skull:
Shattering/fragmentation of the skull or other massive wound, with
most brain tissue lost, or severing of spinal cord.
Face/Neck:
Partial or complete severing of neck (decapitation).
Chest:
Massive gaping chest wound.
Heart:
Heart completely destroyed.
Abdomen:
Disembowelment/evisceration. Treat as a Mortal Wound, but requiring a
Very Difficult Surgery task or Nearly Impossible First Aid task to
stabilise.
Upper
Arm/Leg: Amputation above the
elbow or knee. Treat as a Mortal Wound, but needing a Very Difficult
Surgery task or Nearly Impossible First Aid task to stabilise.
Lower
Arm/Leg: Amputation below the
elbow or knee. Treat as a Mortal Wound.
Hand/Foot:
Partial or full amputation below the wrist or ankle. Treat as a
Mortal Wound but only needing an Average Surgery task or Difficult
First Aid task to stabilise.
Non-lethal
wounds:
For non-lethal attacks, hits to the heart location should be counted
as chest hits.
Stinging
(SG)
The blow stings or twinges, but does not even leave a bruise. The
character suffers no debilitating effects.
Bruised
(BR): The character has a nice
shiny bruise where they were hit. Actions involving the affected
location are at -1 per BR wound state for five minutes.
Stunned
(ST): The location is
temporarily incapacitated for 1D3 Rounds, after which the wound state
is reduced to Bruised for five minutes. If the skull or face/neck is
hit, the character is semi-conscious and cannot act (they just
stagger around or fall over). If an arm or hand is hit, they drop
anything held immediately, including ropes or ladders which you are
hanging on to. If a leg or foot is hit, they cannot walk on it and
must make an Average Athletics roll to stay on your feet. If both
legs are affected at once they automatically collapse, unless already
seated or lying. A ST wound state to the chest or abdomen leaves you
winded – you cannot run and you can only walk at ⅓
normal speed.
Knocked
Out (KO): You are knocked
unconscious or crippled by the pain of the blow for 2D6+6 rounds,
after which the wound state is reduced to Bruised for five minutes.
If the skull or face/neck is hit, you are knocked unconscious. For
the chest and abdomen, you are conscious but incapacitated and unable
to stand. A limb is rendered useless, and in the case of a leg or
foot the character must make a Difficult Athletics roll to remain
standing.
A
DA result from a
non-lethal attack means that bone has been broken, counting as a
Crippling Wound (CW)
result from the lethal attack section. If the minimum roll for a DA
result is exceeded by five points or more, the result is a Mortal
Wound (MW) Thus, a short-range
shotgun blast to a head could be lethal even if the victim was
wearing a helmet that stopped the shot from penetrating. If the
minimum roll for a DA result is exceeded by ten points, the result is
a Death/Amputation (DA)
wound. This reflects massive crushing damage or blast injuries from
explosions.
Quick
and Simple Wound Resolution
The rules for calculating wounds given above are detailed but
complicated. They are probably too time-consuming to use in a fight
between more than a handful of people. Furthermore, it doesn't really
matter whether a nameless, faceless goon who's only in the game for
one fight gets a flesh wound in the arm or the leg. Arguably hit
locations should only be used for Player Characters and important
NPCs, or not at all.
With that in mind, here is a simplified version of the wounding
rules.
First there are no hit locations, and so no location modifiers to the
wound roll.
A character's AV is based on the armour or cover protecting their
torso, or the AV of the best-protected body location if the torso is
uncovered.
A D6 is rolled to see if the attack hits the character's armour or an
unprotected location. The number needed for this 'saving throw' is
based on how much of the character's body is armoured or behind
cover, which is counted in 'blocks'. The torso is two blocks, the
head one, the arms one and the legs two, for a total of six for the
whole body.
Blocks
Protected Saving
Throw
1 6
2 5
or more
3 4
or more
4 3
or more
5 2
or more
6 Automatic
Thus a character wearing a bullet-proof vest and a helmet would use
the AV of the vest, but only on a D6 roll of 4,5 or 6. Otherwise an
unarmoured location has been hit.
Penetration is handled more or less as normal: If the attack's PEN is
less than the target's AV, the attack fails to penetrate. If PEN and
AV are equal, the attack penetrates but with a -5 modifier to the
wound roll. If PEN Is greater than AV, the attack penetrates with no
modifier to the wound roll. We don't need to bother about non-lethal
hits from high-damage weapons that fail to penetrate.
Wounds are rolled for on the wound table above, but with no modifiers
for location, as already mentioned, and no modifiers for
previously-suffered wounds. However, the modifiers for the Size stat
are still used, as does the Strength modifier to DC for melee and
unarmed combat attacks. The simplified wound results are as follows:
Lethal
Attacks:
Scratch
(SC): no effect
Flesh
Wound (FW): -1 to all stats
until healed. The character must make a Nerve check for morale or
take cover, flee or surrender (as the GM deems appropriate)
Crippling
Wound (CW): all stats halved.
If two CWs are suffered, divide stats by three, if three CWs divide
by four etc. The character must make a Nerve check for morale at -3
or take cover, flee, surrender or pass out (as the GM deems
appropriate).
Mortal
Wound (MW): as CW, but the
character must make a toughness check to avoid dying every round (+1
to the roll for every round after the first) until they are
stabilised by successful a First Aid task, roll a 1 (the wound
stabilises on its own) or they fail the roll and die. The character
must also make a Nerve check for morale at -3 or take cover, flee,
surrender or pass out (as the GM deems appropriate).
Death/Amputation
(DA): the character is killed
immediately.
Non-Lethal
Attacks:
Stinging
(SG): no effect
Bruised
(BR): -1 to all stats for five
minutes
Stunned
(ST): the character cannot act
for 1D3 rounds.
Knocked
Out (KO): the character is
unconscious and out of the fight.
Super-Simple
Wounding Rule:
This rule is presented in case things are still to complicated, or in
case anyone wants to run a skirmish battle game with these rules.
Scratch
(SC) and Flesh Wound
(FW) results have no effect.
Crippling
Wound (CW), Mortal
Wound (MW) and Death/Amputation
(DA) results mean the character
is 'down' and out of combat as a casualty – injured, dying or dead
in each case.
