Shot through the heart, and you’re to blame
+Peter V. Dell’Orto discussed how much damage is required to kill in GURPS hand to hand combat the other day. In it, he notes:
Yeah, it’s true. Gunfire can push you to -5xHP so easily I decided it wasn’t even worth discussing. But a post about different pistols and rifles and kills might be worth doing for Doug. Even a “mere” 2d+2 pistol is only a couple of vitals shots from automatic death.
Challenge accepted, though it’s somewhat meager. Just as a setup, you of course take your first risk of death at -HP, and autodeath at -5xHP, meaning that for a healthy guy, you must suffer 2xHP and 6xHP injury in one shot. I’m going to play a bit here, and take that as 24 HP and 72 HP of injury. And I’m doing that very, very much because that’s the average roll on 7d and 21d; for a max roll, you can’t get there unless you’ve got 4d and 12d. That makes the numbers work out to just a bit of overkill (or just the right amount of kill for a slightly-strong target), but also even numbers of dice.
I’m going to be expressing a lot of things in dice rather than HP.
Edit: Some good comments about “out of the fight” and “dead” not being the same in GURPS. Point profoundly taken, but the question that Peter tossed my way was “how much damage is required to kill.” I took that as “in one turn,” because bleeding is optional and (in my opinion) factored into the decision to not deal with blow-through in the 4e rules.
One Word About Armor (for now)
Armor gets a one-word mention here: it’s what you have to bypass to hit the creamy center, and it can get pretty high at TL7 and TL8.
Vitals and Brain
The fact that the brain and vitals’ wound multipliers are x3 and x4 regardless of injury type or size (they overwrite bullet size) means that it becomes generic to look at.
Vitals: To threaten death to the vitals, you must bring a weapon to the fight that does at least 1d+1 or 1d+2. To threaten a single death check on an average roll means you need at least 2d+1. Auto-death is from 4d and 7d, respectively.
Brain: It’s even lower for the brain, of course, but you’ve got that pesky DR 2 skull to deal with. That makes the minimum 1d+2 for the brain, and about 2d+1 for an average shot to force a single check. For auto-death, you can’t do that without a minimum of 3d+2, and you won’t do it on average without 5d+3 or 6d-1.
Weapon me: The short version, with some slop in it. You can get by with a .22 LR pistol (Ruger Standard Mk1) to the vitals, but not the brain, due to the skull armor. A single pellet of buckshot is likewise fine if it hits the vitals, but not the skull. To theaten either vitals or skull, you need 2d+1, which is carry-sized (4″ barrel) 9mm like the Glock 19, Walther P99 or PPQ, or a .40 S&W or 9mm subcompact. In short, a 9mm or .40S&W pistol. Note that a .45 ACP will do for the vitals but not the skull, since it’s only 2d or 2d-1.
For auto-death, you’re looking at weapons that can do 4d minimum to 7d on average for the vitals, and 3d+2 to about 6d-1 for the brain. In short, the only SMG that meets these minimum criteria is the H&K MP7. The P90 comes the next-closest, but doesn’t get there. Basically, upgrade to a full-power subcaliber cartridge to have a chance: even the 10.5″ barrel on a 5.56x45mm carbine like the XM177E1 Commando (4d pi) will do it, but to get to auto-death territory, you want something with at least a 6.8x43mm cartridge (6d from a 16″ barrel) all the way up to a battle rifle (7d) in 7.62x51mm.
Shoot a lot: These are all one-shot numbers. If you are firing at an unarmed person and skilled enough to hit a bunch of times, nearly any weapon can do the trick. All SMGs have Rcl 2 from High Tech, so if you can eke out enough skill to absorb the -3 to the vitals and -2 to hit twice, all of a sudden that P90, with 50 shots, looks pretty attractive. Two shots to the vitals with a 4d carbine racks up 12d in injury to an unarmored foe, which is a fast ticket to auto-death at -5xHP as well.
Torso
The numbers for the torso are subject to injury modifiers. But you still need 4d to 7d injury to threaten a death check with a single shot to the torso. That is:
Death check thresholds – one shot to torso
8d pi- minimum
4d pi minimum
2d+2 pi+ minimum
2d pi++ minimum
For a handgun, you have to go a bit nuts. A .44M will do it, so will monsters like a Super Redhawk in .454 Casull or the movie-popular Desert Eagle, whose .50AE cartridge cracks the scale at 4d pi+. I’m sure there are others in the overkill department. Interestingly, a full-sized .40S&W such as the H&K USP, the Glock 22, or the Walther PPQ with the 5″ barrel will all hit 2d+2 pi+, so it’s barely possible to threaten a one-shot death check with a service handgun.
Most assault rifles are in the right range here. Most SMGs aren’t. To average a death check, you need 6d-7d or so injury, and so that’s two hits from a pi+ weapon of decent velocity, or two from a pi rifle type. One hit from a battle rifle in .308 or .30-06 will do it too.
Auto-death is either “bring a .50BMG” whose 6dx2 pi+ technically still doesn’t cut it for auto-death to the torso (18d vs 21d), or shoot people a lot. Three rounds to the torso with a battle rifle will do it.
Final Word on Damage
The moral of the story here is either have a low-damage weapon that you can hit with a lot in one turn, or a much higher one. If you’re looking to drop a foe in one shot, the primary target for an unarmored person is the vitals, not the skull. Skull shots are cool and all but the difference betwen -3 and -7 is two extra hits to the vitals, plus the DR 2 for the skull actually makes it a tougher kill for pistols especially.
More Words About Armor
The torso armor table on High Tech p. 66 hits the key bits that throw the above calculations to the wind a bit. A fragment vest is the equivalent of about 1d+1 right off the top of your weapon, and more serious protection like a a concealable or assault vest is more like 3d+2. That’s before you add trauma plates worth another 7d. If the “dragon skin” concept meets or exceeds manufacturer’s claims (there was some controversy in the past), it’ll soak up about 14-15d (defeating 7.62×51 AP ammo at 2800fps is no joke).
At that point, the torso and especially the vitals become effectively non-viable.
Modern ballistic helmets also grant about 3d+2 (DR 12) to the skull. The Advanced Ballistic Helmet (Pyramid #3/57) is DR 16 (4d+2).
In both of these cases, only a direct hit from an assault or battle rifle, or a powerful SMG with AP ammo will do.
You may even have to shoot at the face, assuming no visor, and hope for that 1 in 6 chance of hitting the skull anyway (optional rule, p. 16 of Tactical Shooting).
With proper armor, the available targets start to get limited. Face, maybe the neck, and limbs.
Parting Shot
In a way, there are no surprises here. Aiming for the vitals is a good idea if you have a defensive weapon (read: decent power handgun) and can end a discussion promptly – but likely not force a target into the -5xHP real of auto-death.
Well, given those numbers, it really does explain the fetishization of the double-tap and related drills.
"If it's worth shooting, it's worth shooting twice."
"Two in the chest, one in the head, keeps you healthy and the other guy dead."
Let's also bear in mind that a lot of movie shootings just produce unconsciousness, followed perhaps by bleeding to death; one doesn't need an automatic one-shot kill to take someone out of the fight.
I think it's important to remember that dropping your target doesn't necessarily mean that you kill them, "instantly". Basically only gamers care about immediate death in seconds. In the real world lethality is measured over minutes. If you are using all the rules in Martial Arts and Tactical Shooting* you can get incapacitation from significantly sub-lethal shots (just as in real life!).
Even against the best body armor, you can still cause more than enough shock and injury to eliminate a combatant. Remember that the area covered by the trauma plate in the front and back is really only the "Chest" location from Low-Tech, and the side coverage is really only about half of that. Shots to the abdomen, neck are only against the soft armor and shots to the underarm are against no armor at all. Limbs are still nearly impossible to armor.
*Especially when combined with some of the fear rules from Horror.
Roger and Cole: point taken for both of you. But the question Peter bump-passed me was on death, not incapacitation. So I treated that. For KO, it's rather a lot simpler: half the lower value. Which means darn near any weapon to the vitals will get it done. Heck, a 1d+1 pistol will get an average guy to -HP 2/3 of the time to the vitals and half the time to the skull.
I've long wanted to play a character who did his assassinations with a .22 Short revolver, just to show up the guys that insist on hand cannons.
I find it wild that a .40 cal Glock isn't a viable one shot kill in the real world with a head shot. I fired thousands of rounds in mine over the years and that really surprises me. Is this reflective of real world data?
A max damage roll is 11-12 points x4 for -3x to -4x HT. If he's not dead instantly, he's going to expire by blood loss. He's also going to KO.
Just read a really interesting article from a medical examiner who is also involved in shooting, and he really goes off on how important bullet mass is over muzzle velocity – too much chance of bones getting in the way and deflecting off in a non-lethal direction. He calls the .40 a good weapon for one shot drops – not kills, mind, but one shot to put a man out of action – but prefers the .45 for the job, and specifically calls out .380 and 9mm for needing a second round to do the job.
It's an old argument, and one that will not be resolved in our lifetime
Well, everyone has their favorite calibers. Me, I've got weak wrists. Hot enough 9mm can make me an inaccurate putz. I prefer a wee caliber that I can control effectively, because a .32 that hits the target is better than a .50AE that shoots down a passing bird overhead.
All right, lets try this with a little less crazy vet. 🙂
In the real world a "one shot kill" means that was incapacitated and died from the wound without recovering… eventually. Only gamers care about "instant" death. Medical and military definitions of lethality are in minutes, not seconds. Your Glock is very likely to cause an incapacitating and lethal wound with good shot placement. That it isn't very likely to do so "instantly" is actually completely irrelevant to you in the real world.
Human bodies can be very resilient, and generally can't fail completely in less than a minute. Really the only truly "instant" kills are wounds that destroy a large portion of the brain stem.
People have been known to crawl (and even shoot!) when the lower half of their body was completely blown off by explosive shrapnel. Even decapitation doesn't result in "instant" brain death.
Great discussion. I'd love to see a follow up post addressing what the optional Body Hits rules in High Tech mean for all this. The 1 in 6 chance of a Vitals hit for every Torso hit makes life brutal and short if you are using automatic weapons, since you no longer have to absorb the -3 on attack rolls to get a chance at hitting the Vitals. On the other hand, you also lose the ability to deliver more than HP damage at once if you DON'T hit the vitals.
In my games, we've been using Body Hits with a common house rule to increase the max wounding numbers of pi+ and pi++ projectiles (which also reduces the wounding maximum of pi- rounds that miss the vitals) and that seems to work quite well. Bleeding is just an integral part of the system for me–I can't play a game that's trying to be remotely realistic without those rules. Someone put up a pre-calculated "average damage from blood loss" post at one point, and I find that very useful for estimating lethality on NPCs who I have no desire to roll for. (Here it is: http://forums.sjgames.com/showpost.php?p=1575291&postcount=27).
This is a reasonable request, and I'll probably follow up this post with a likely more interesting one about probabilities and strategies for incapacitation. That is, how to force a failed HT roll for KO.
Also, in some of my old TL8-ish games, I used to just say 'any torso hit that hits by 3+ hits the vitals," obviating the need to aim for them. Since at least the way I was trained, you ALWAYS aim for the vitals in the center of the body. I suppose that it would be fine to make it "make it by 4 or 5" on any roll, or deliberately target them at -3, miss by 1 hits torso, so that taking the Aim still makes sense, but it's worked well in play.
Am I interpreting your second paragraph correctly, Jake, when I restate it to say that pi+ and ++ weapons can do more than 1xHP damage, while pi- can't even do 1xHP damage?
A house rule that I used to use was to cap blowthrough with the wound channel modifier x HP, but then have a bit more serious bleeding rules based on the non-blowthrough damage.
So a .45ACP would blow through after 15 HP (but never roll that high) penetration, a 9mm or a .223 would both blow through after 10HP. But bleeding would be figured from rolled damage so about 2 HP per minute for the 9mm, and 3-4 HP per minute for the .223.