Re: Survivable Guns Realism
 

EDIT: It seems that you are referring to brain tissue, which I seem to recall having well documented remote wounding effects. The rest of this post therefore doesn't apply to you.

The incapacitating effect of ballistic pressure waves is a subject of hot debate and not in the realm of solid fact at all yet. Which is not to say that it's wrong -- since I have a personal hunch that ballistic pressure waves *do* cause incapacitation -- but the verdict remains out, and a lot of ballistics authorities dismiss the whole idea as hokum.

Re: Survivable Guns Realism
 

Tactical Shooting mentions this (p6), that it would apply to Skull hits. I've heard before that Vitals typically suffer as well, and have also read that it may be possible for it to come into play when the bullet passes perilously close to the brain stem (the shockwaves hitting that and causing incapacitation). The first two are probably covered well by the wounding modifiers (even without considering lack of blowthrough caps, which may not be strictly necessary), the last I don't entirely buy but as such a wound would almost invariably be a Major Wound, I think the basic HT roll to avoid knockdown/stunning is sufficient.

A bullet breaking up or tumbling should be covered by an increase in wounding modifier (indeed, this is the reason 5.56 is pi instead of pi-). While I'm not certain on the breaking up bit (although I think that typically only happens when the bullet tumbles, or when bone is hit, but that's a whole different problem), to my knowledge the 7.62 rounds very rarely tumble.

Ideally, rifle rounds should have something like a "tumble threshold" - once they've done a set amount of damage without blowing through (using variable blowthrough rules), they get +1 to size due to tumbling. Tumbling for far enough might reach another threshold, wherein they get another +1 to size due to fragmenting. As each round would have different thresholds (and different ranges at which those thresholds apply), that would probably be too much work for what it accomplishes.

Tactical Shooting lists it as a myth, but that doesn't necessarily mean Hans is right on that point (I strongly suspect he is, however). For what it's worth, TS does mention that the effect would work when shot in the Skull, but also notes that the x4 multiplier Skull wounds suffer from is sufficient to cover this problem.

Re: Survivable Guns Realism
 

Spin stabilized rounds that don't tumble in flesh are essentially nonexistent -- the amount of stabilization required for air doesn't do the job when you hit something 800 times denser. Fin stabilized rounds might just punch a hole through and come out the other side, it's a problem with flechette rounds.

Re: Survivable Guns Realism
 

Which should manifest in wounding modifier, and is only quite indirectly related to the raw damage.
Lack of blowthrough caps is strictly necessary, considering that if you had them it would be literally impossible to be instantly killed by a bullet. Remember that the by-the-book caps are on wounding and are not adjusted by wounding modifiers.

If Vitals didn't remove the wounding cap, a .22 lr to the vitals would be about the same effect as a more serious bullet, or for that matter a 25mm armor-piercing round.

Granted you could have blowthrough caps on vitals wounds that wouldn't have that problem, but they'd have to be quite different from the actual rules.

Rolling for knockdown and stunning is not addressing the problem at all.



I've seen it put forth that the liver, unlike most tissues, is notably inelastic and therefore temporary cavity effects within it may not be as negligible as they probably are elsewhere.

Re: Survivable Guns Realism
 

Which doesn't mean you couldn't change that. There's a pretty strong argument for blowthrough caps being caps on damage, not wounding.

Re: Survivable Guns Realism
 

If this is indeed the case - that virtually all rifle rounds tumble in flesh - it implies rifles should simply get an outright boost to damage category, as they are effectively 1 size category (or perhaps 2 for extremely long bullets) larger in the body. Of course, they're going to penetrate much worse in flesh as a result, justifying a (.5) or so Armor Divisor against soft tissue (and anything behind the target in the case of a blowthrough). GURPS doesn't do Pi larger than Pi++, but houseruling that in is easy enough (if memory serves, you have a wounding system to that effect on your site).

This is true, but blowthrough being capped by injury rather than basic damage seems rather nonsensical and as such I tend to ignore it. I was musing with the (unfortunately-unstated) assumption that blowthrough was instead capped by basic damage, and wounding modifiers came in later. If we do that, it means a shot to the Vitals would still blowthrough at 10 damage, but injury would then be 30 HP, dropping the target to -2xHP for two death checks and a -10 to Bleeding checks and Surgery rolls to stop said bleeding. Things change, of course, if using houserules that allow wounding and location modifiers to stack.

I was simply considering the possible hydrostatic shock as a justification for why a particular Knockdown/Stunning roll failed - the bullet passed close to the brain stem and the internal shockwave jumbled things up a bit, causing the target to become disoriented and fall down - or for a particularly bad roll, causing the target to outright lose consciousness. For reference, the information I saw about the brain stem bit indicated a temporary effect, akin to KD/KO.

I think I've read that before too, but don't know enough about liver injuries to know what their effect in GURPS would be. Hit locations 2-4 on the Abdomen correspond to the digestive tract; saying hit location 4 is instead the liver and having full damage apply to bleeding rolls might be appropriate.

Re: Survivable Guns Realism
 

My understanding is that livers are prone to catastrophic bleeding. I'd figure the liver as being part of the abdomen portion of the vitals, along with the kidneys.

Re: Survivable Guns Realism
 

Non deforming long aspect rounds of "normal" configuration always tumble changing back for front _once_. This si because pointy end first is not inherently stable. That has to be spun rapidly for stabilization.

The greatly enhanced drag from flesh stops the spin and the bullet switches to the more naturally stable pointy end last mode. most rifle bullets break up halfway through this process as the stresses of going through flesh sideways are excessive.

There are exceptions to these processes.

Very solid types of bullets (like AP) are solid and strong enough nthat they don't break up. Older byllets with thicker jackets than is common today sometimes survive this sort of thing too even if they aren't quite AP.

Pistol bullets generally don't do this because they are short aspect.

Jacketed Softpoint rifle rounds (like almost alk civilian hunting rounds) become much shorter and move their center of mass when they expand. So no tumbling but they can break up.

The SS190 rounds for the FN PDW don't tumble because they are so point-heavy that they are stable pointy end first.

There are no doubt other exceptions but maybe you get the idea.

Re: Survivable Guns Realism
 

Vitals was my initial thought, but I'm not certain incapacitation from liver hits is anywhere near as rapid as from heart/lung (interruption of oxygen transport) and kidney (toxic shock) hits, and the apparently-inelastic nature of the liver may make it somewhat unique in that regard. A new hit location, possibly with comparable bleeding to the Vitals and no blowthrough cap, seemed appropriate. If you have no blowthrough cap on Vitals, however, lumping them together probably isn't too bad of an option.

Thank you, this post was most useful. I remember reading similar information before, but didn't really think of it.

For this single-tumble event, I'd say simply using the normal wounding modifier (it probably doesn't spend enough time oriented sideways to make a real difference, and wounding modifiers are based on nominal caliber, which is the width of the back end anyway) and giving them a poorer armor divisor for punching through flesh would work. Rounds that break apart during this process should get at least a +1 to wounding modifier and have an even poorer armor divisor. For rounds that don't tumble, it may be appropriate to downgrade the wounding modifier a step, as the conical shape may allow it to push some of the tissue aside rather than crushing through it, leaving a smaller wound channel (I think this is part of the justification of why AP rounds suffer from a reduced wounding modifier).

Re: Survivable Guns Realism
 

Toxic shock? How fast-acting is that? And does it happen if you only lose one?

I thought the fast damage from a kidney was bleeding...