Base gun damage on calibre and gun size; armor divisor on kinetic energy?

[Rupert]

Originally Posted by Fred Brackin

I find it's jsut as likely that guns aren't lethal enough.

Put a bullet from a .45 aCP into a target's Brain and that's 7 pts of damage -2 pts for his Skull (which is part of the problem) and then the remaining 5 pts get multiplied by 4. 50% of HT 10 NPCS will survive and it's actually worse than that because you won't always roll as high as 7 to begin with.

Rolling a 2 means they take no damage. 3-4 means they're still at positive HP and if they make the HT-10 check can happily keep fighting (though possibly at 1/2 move and dodge). 5 means they're negative, but not at risk of dying, and might keep fighting for a bit if they pass their knockdown and consciousness checks. 6-9 means they have to make a single death check. 10-11 mean that they have to make two checks. 12 means they have to make three.

The overall chance of dying from that single .45 ACP bullet to the skull is ~40%. The odds of remaining conscious are something like 18%.

Brain and vitals arguably should still be affected by size modifiers on piercing damage, though that might make .45 hollow points to the vitals a little bit too lethal. Maybe if the 'multipliers' added like CFs do on gear, so a pi+ to the brain would do 1 + 3 + 0.5 = x4.5 damage.

[Tinman]

Fred Brackin, I hear you & as I said in my post, I think guns are fine.

The example of the .45 is an odd case for a bunch of reasons, however with a 9mm pistol you average 28 points of injury, giving 3 HT rolls to stay alive & a major wound roll @ HT-10.

In both cases, the HT-10 for major wound to the head is a fight ender & with bleeding rules the target will usually bleed to death in only a few minutes.

[Varyon]

Originally Posted by Rupert

Rolling a 2 means they take no damage. 3-4 means they're still at positive HP and if they make the HT-10 check can happily keep fighting (though possibly at 1/2 move and dodge). 5 means they're negative, but not at risk of dying, and might keep fighting for a bit if they pass their knockdown and consciousness checks. 6-9 means they have to make a single death check. 10-11 mean that they have to make two checks. 12 means they have to make three.

The overall chance of dying from that single .45 ACP bullet to the skull is ~40%. The odds of remaining conscious are something like 18%.

The full breakdown for damage is:

Damage	Prob	Result
2	2.8%	No Injury
3	5.6%	4 HP, HT+0 check vs Stun
4	8.3%	8 HP, HT-10 check vs Stun
5	11.1%	12 HP, as above plus HT check to stay conscious each round*
6	13.9%	16 HP, as above
7	16.7%	20 HP, as above plus HT check to survive
8	13.9%	24 HP, as above
9	11.1%	28 HP, as above
10	8.3%	32 HP, as above plus 2nd HT check to survive
11	5.6%	36 HP, as above
12	2.8%	40 HP, as above plus 3rd HT check to survive

*I think this is at -1 at -1xHP, -2 at -2xHP, etc, but I'm not certain

Staying conscious requires either succeeding at the check vs stun or failing by less than 5. This is a given for 2 damage, requires a roll of 14 or less for 3 damage, and requires a roll of 3 or 4 (Critical Success) for 4 damage or more. That's 0.028 (1*0.028) + 0.051 (0.9074*0.056) + 0.017 (0.0185*0.916), or about a 9.6% chance of remaining conscious, not even considering the 50% (or less) chance of staying conscious each additional round 83.3% of the time (5 damage or higher).

As for survival, that's a given (ignoring bleeding) between 2 and 6 HP, requires one roll of 10 or less between 7 and 9 HP, two rolls between 10 and 11, and 3 rolls at 12. Probability of survival is thus 0.583 (1*0.583) + 0.21 (0.5*0.417) + 0.035 (0.5*0.5*0.139) + 0.0035 (0.5*0.5*0.5*0.028), or about an 83% probability of survival.

So, less than 10% chance of staying awake, but 83% chance to not die outright. Both are probably higher than is realistic, of course, but at least the first isn't terribly off, and the second plummets when bleeding rules are used.

[Tomsdad]

Originally Posted by Varyon

The full breakdown for damage is:

Damage	Prob	Result
2	2.8%	No Injury
3	5.6%	4 HP, HT+0 check vs Stun
4	8.3%	8 HP, HT-10 check vs Stun
5	11.1%	12 HP, as above plus HT check to stay conscious each round*
6	13.9%	16 HP, as above
7	16.7%	20 HP, as above plus HT check to survive
8	13.9%	24 HP, as above
9	11.1%	28 HP, as above
10	8.3%	32 HP, as above plus 2nd HT check to survive
11	5.6%	36 HP, as above
12	2.8%	40 HP, as above plus 3rd HT check to survive

*I think this is at -1 at -1xHP, -2 at -2xHP, etc, but I'm not certain

Staying conscious requires either succeeding at the check vs stun or failing by less than 5. This is a given for 2 damage, requires a roll of 14 or less for 3 damage, and requires a roll of 3 or 4 (Critical Success) for 4 damage or more. That's 0.028 (1*0.028) + 0.051 (0.9074*0.056) + 0.017 (0.0185*0.916), or about a 9.6% chance of remaining conscious, not even considering the 50% (or less) chance of staying conscious each additional round 83.3% of the time (5 damage or higher).

As for survival, that's a given (ignoring bleeding) between 2 and 6 HP, requires one roll of 10 or less between 7 and 9 HP, two rolls between 10 and 11, and 3 rolls at 12. Probability of survival is thus 0.583 (1*0.583) + 0.21 (0.5*0.417) + 0.035 (0.5*0.5*0.139) + 0.0035 (0.5*0.5*0.5*0.028), or about an 83% probability of survival.

So, less than 10% chance of staying awake, but 83% chance to not die outright. Both are probably higher than is realistic, of course, but at least the first isn't terribly off, and the second plummets when bleeding rules are used.

Nice!

Another factor with bleeding is that a 10hp target with a 8 point injury it's not going it take many failed bleeding rolls to take them into negative HPs and into rolls to stay conscious if you are taking actions, before failed bleeding takes them into rolling to stay alive.

Of course at the rate of bleeding checks that still lots of potential action being taken before bleeding gets you there

[DouglasCole]

Originally Posted by Varyon

Both are probably higher than is realistic, of course, but at least the first isn't terribly off, and the second plummets when bleeding rules are used.

I have discussed "instant death, other than central nervous system" with physicians and trauma experts, and almost invariably their version of "instantly" for nearly any wound is "in less than a minute!" (The exclamation point is a description of them trying to impress on me how FAST that is.)

Assuming a wound that blows through and either drives someone to 0 HP or -1xHP, you're talking about losing 4-5xHP in 30-60 GURPS turns due to bleeding and knock-on effects of bleeding.

On the low end (fast death), that's a multiple of HP every six turns, on the high end it's more like a multiple of HP every 15 turns.

That second one looks like roll HT every second, lose 1 HP to bleeding if you fail, takes a serious effort in First Aid or Physician to make it stop. The first one is 2 HP per second, or perhaps 1d on a failed HT-3 roll or so for a HT 12 adventurer. Or HT-1 for Joe Average.

So the difference between perceived reality and GURPS reality here is

1. Instant incapacitation is fail a KO roll, not dead.
2. Death is rarely "instantaneous" in real life, on a GURPS tactical time scale.
3. With appropriate lack of intervention, losing something like 1 to 1d HP on a failed HT roll due to mild to severe bleeding gets you in the right ballpark of actual time to die for vitals and head wounds that aren't instantly fatal

Gunshot wounds can be - and are - deadly. But not uniformly or invariably so, and modern medicine does astounding things, given the chance.

[Anthony]

Note that part of the reason you don't have much in terms of 'death in less than a minute' is uncertainty about what you even mean by dead. Unless the brain gets splattered, it simply takes a while to shut down (generally a few minutes for irreversible brain damage), though you can declare quite a bit earlier "unconscious and no chance of recovery".

[RyanW]

Originally Posted by Anthony

Unless the brain gets splattered, it simply takes a while to shut down (generally a few minutes for irreversible brain damage), though you can declare quite a bit earlier "unconscious and no chance of recovery".

The technical term is moribund. Even JFK wasn't pronounced dead until 22 minutes after arriving at the hospital, when no more heart activity was detected.

[Tomsdad]

Originally Posted by DouglasCole

I have discussed "instant death, other than central nervous system" with physicians and trauma experts, and almost invariably their version of "instantly" for nearly any wound is "in less than a minute!" (The exclamation point is a description of them trying to impress on me how FAST that is.)

Assuming a wound that blows through and either drives someone to 0 HP or -1xHP, you're talking about losing 4-5xHP in 30-60 GURPS turns due to bleeding and knock-on effects of bleeding.

On the low end (fast death), that's a multiple of HP every six turns, on the high end it's more like a multiple of HP every 15 turns.

That second one looks like roll HT every second, lose 1 HP to bleeding if you fail, takes a serious effort in First Aid or Physician to make it stop. The first one is 2 HP per second, or perhaps 1d on a failed HT-3 roll or so for a HT 12 adventurer. Or HT-1 for Joe Average.

So the difference between perceived reality and GURPS reality here is

1. Instant incapacitation is fail a KO roll, not dead.
2. Death is rarely "instantaneous" in real life, on a GURPS tactical time scale.
3. With appropriate lack of intervention, losing something like 1 to 1d HP on a failed HT roll due to mild to severe bleeding gets you in the right ballpark of actual time to die for vitals and head wounds that aren't instantly fatal

Gunshot wounds can be - and are - deadly. But not uniformly or invariably so, and modern medicine does astounding things, given the chance.

I definitely agree with your point that death is rarely instantaneous in real life and what often happens in regards to bleeding out, but the current bleeding rules aren't fast enough to model the kind of loss you describe above. Of course you could argue that some of the extra HP lost due to location injury mods represent the overall effects of that fast bleeding, but in the system it's either enough to trigger a Death save or not (the mortal wound optional rule is relevant here as well).

I wonder if it is worth some new optional rule for faster bleeding for some injuries/locations. On a metagame point sub systems that have people helplessly watching their character bleed out at a faster rate than they can address with mundane means can be seen as unfun. So I'd make it optional and situational.

Taking less time on first aid / surgery rolls might work but that would be negative mods on top of negative mods.

[Tomsdad]

Originally Posted by Anthony

Note that part of the reason you don't have much in terms of 'death in less than a minute' is uncertainty about what you even mean by dead. Unless the brain gets splattered, it simply takes a while to shut down (generally a few minutes for irreversible brain damage), though you can declare quite a bit earlier "unconscious and no chance of recovery".

Yep I think this is a very good point. In RPGs death is a pretty well defined state and obvious i.e. you are dead when you get to what the system's definition of dead is. In RL it's often less obvious (and often a case of retroactive conformation)

Which brings up another point the immediate results of an attack in terms of their perceived effects vs. actual long-term results included being pronounced dead either at the scene or later on.

How often do we see depictions of a bullet to the head in films and other media where those hit just drop to the ground and stop moving, scene moves on. To me that's what failing the HT-10 roll by 5 looks like a lot of the time. It's often not necessary to the story to actually precisely time stamp the exact point of irrevocable brain death. (and even the traditional signs of death in media e.g. final death rattle, relaxation of grip, glassy eyes to camera etc are not actual sure fire signifies of death in RL).

[Varyon]

Originally Posted by DouglasCole

I have discussed "instant death, other than central nervous system" with physicians and trauma experts, and almost invariably their version of "instantly" for nearly any wound is "in less than a minute!" (The exclamation point is a description of them trying to impress on me how FAST that is.)

Of course, what we're discussing is, in fact, a CNS wound - a .45 ACP to the brain (via Skull). I don't know exactly how quickly and reliably that tends to make someone dead, but I'd imagine survival - even with immediate intervention - is rather the exception. Going with an average 20 HP Injury, if I'm remembering the way bleeding (and bleeding from Skull hits) function, that's a 50% chance to initially survive (and ~34% chance of "only" being mortally wounded, with instant death happening ~16% of the time), then an HT-4 roll (-1 per 5 HP lost) every 30 seconds to avoid bleeding. Rolling a 5 or 6 three times in a row is pretty unlikely, so natural recovery likely only happens with a Critical Success (3 or 4). With a 1.85% chance to stop bleeding each check, a 7.39% chance to avoid losing HP but continue bleeding, an 86.12% chance to lose 1 HP, and a 4.62% chance to lose 3 HP (Critical Failure on 16+), you're looking at an average loss of 1 (0.9998) HP every 30 seconds. You have a ~15% chance to stabilize before the next death check threshold, ~30% by the threshold after that, ~42% by the threshold after that, and ~52% just before reaching -5xHP. Overall, the chance to survive an average damage .45 ACP to the Skull isn't great without intervention, but isn't atrocious either. 16% die outright, 34% suffer mortal wounds, and 50% survive without qualifiers. Of the latter 84%, 15% (12.6%) stabilize on their own before hitting the next threshold. Of the 71.4% remaining, 50% (35.7%) keep going, 17%* (12.14%) suffer mortal wounds, and 33% die (either from failing by 3+ or failing at all when already mortally wounded) at 300 seconds (5 minutes). Of the remaining 47.84%, 15% (7.18%) stabilize on their own before hitting the next threshold. Of the 40.66% remaining, again 50% (20.33%) keep going, 17%* (6.91%) suffer mortal wounds, and 33% die at 600 seconds (10 minutes). Again, 15% (4.086%) stabilize, and of those remaining 50% (11.58%) keep going, 17%* (3.94%) are mortally wounded, and 33% die at 900 seconds (15 minutes). For our last iteration, 15% (2.33%) stabilize, the rest die at 1200 seconds (20 minutes). So, in total, around 26% stabilize on their own. Of those 26%, quite a few are mortally wounded, although I feel working out the probability for that is a bit more time-consuming than I'd like to bother with, but probably less than 50% (13% total), the bulk of which will die from the mortal wounds in several hours without intervention.

TL;DR: So, of those who get an average damage .45 ACP to the noggin and receive no medical attention, ~15% will survive, ~16% will die outright, ~23.8% will die in 5 minutes, ~13.5% will die in 10 minutes, ~7.7% will die in 15 minutes, ~11.1% will die in 20 minutes, and the rest - ~12.9% - will die over the course of hours due to being mortally wounded. Different damage results will shift these around in expected ways (high damage means more die, low damage means fewer die), but this probably isn't terrible to use for the average. Those who get medical attention will fare better, although the clock is certainly ticking (and brain surgery isn't exactly easy). I don't know how close this comes to reality, but I suspect it's rather on the lenient side.

*I'm pretty certain I messed up a bit on the math to calculate the proportion that hit their first mortal wound at each step beyond the first, but I really don't feel like going back and recalculating all of that. Just keep in mind those numbers are probably close but not quite right and you should be fine.