HIGH-TECH-Arrived-Gun Damage

[gmillerd]

I thought that the GURPS stats were derived from real world weapon stats as best as possible with 'standard loads', like what a significant performance or safety trail yielded that could be used for a large swath of weapons.

I recall one of the GURPS blogs/sites where one of the author goes into detail on how to first get close to these numbers uses velocity and bullet load and whatnot, then by taking a estimation of that rounds grain and bullet being bale to modify those numbers to find the max capabilities of the weapon through overloading and what not. Quite an amazing write up, sad that I didn't bookmark it.

Obviously comparisons between generic weapons (though perhaps having calibers or family models) and specific weapons from manufacture specs or other trails is going to differ. It seems the comparisons between various weapons, various ammunitions, people being hit, various locations and circumstances they were hit is futile at best. Other than that the weapons have the tendency wound and slay people effectively.

[DouglasCole]

Originally Posted by Easterner9504

Received G:HT today Pistol damage has some interesting twists.

.45 ACP 2D pi+ Unchanged from basic GURPS
.40 S&W 2D+2 pi+ Basic was 2D so now more powerful than .45 ACP
.45 GAP 2D pi+ Equal to .45 ACP despite smaller case
.357 SIG 3D-1 pi A 9mm equal to .45 ACP (17 vs 18 max damage)
10mm 3D-1 pi+ Pretty powerful, odd it never caught on
.50AE 4D pi+




How exactly does .40 & .357 come out so good in GURPS

GURPS damage numbers are based on muzzle energy divided by cross section of the bullet. At handgun sizes, the cross section factor doesn't change that much, while the energy changes quite a bit.

I can answer a few of your questions, however.

The .45ACP reference bullet is fired typically from the M1911 style pistol, which has a five inch barrel. Many, but not all, .40S&W numbers are fired from much shorter barrels, as they go into compact pistols. Fired from a five inch barrel, like the .45ACP, the 180gr bullet at just over 1000fps rates 2d+2 in GURPS. If you look through particular weapons tables, you'll find compact .40S&W guns often lose a point or two of damage. In fact, at 127mm barrel, MY numbers, which aren't those of high tech, give EXACTLY 9pts of damage (2d+2); losing even 1mm of barrel moves it down to 2d+1, and out of a 76mm or smaller barrel, will only get 2d.

As far as being better than the .45ACP, within GURPS granularity of where the pi vs pi+ falls (.40 or 10mm), them's the breaks. If you wanted to, you could give the .40S&W a wound channel mod of 1.2, and the .45ACP 1.5, but in GURPS terms, the .40S&W and even more so, the 10mm Automatic are JUST BETTER than the .45ACP. As far as the .45GAP, with a shorter but stronger case, you can use more energetic powder to push the bullet to equivalent velocities. The .45ACP is only a 17,500psi cartridge; the 9mm is 32,500psi, and the .357M and .40S&W are 35,000psi. If you used a high pressure cartridge like those, you wouldn't NEED a long case to get equivalent or even slightly superior performance out of a 230gr projectile!

The .357SIG cartridge fires a 125gr bullet approaching .357Magnum speeds. This is an excellent round for penetration, which is what GURPS damage numbers primarily represent.

[DouglasCole]

Originally Posted by SimonAce

I'd guess the .40 S&W load in basic is 180 grains @ 900 Feet per second where as the .40 load in High Tech is probably the more effective 155 grains @ 1150 - like a bigger 9mm. Hence the figures

The loss in weight going to 155gr means that the overall KE of the projectile doesn't change enough between the 180gr load (180gr at 300m/s; 525J) vs the 155gr load (155gr at 350m/s; 620J) to throw you over the edge to the next damage rating (3d-1, or 9.5pts average damage).

This, by the way, is often the case; there is seldom, if ever, more than a little bit of difference in GURPS terms between most of the common factory loads. Much, but not all, of the velocity gain is just due to the lighter bullet, and in GURPS, constant KE gives constant damage, all other things being equal.

.357 is scary powerful -- base load from a 4" barrel is 158 grains @ 1250 fps (40% more weight and 10% more velocity) for lower tech (tl6) The main police load (by Tl7) is stomping 125 grains @ 1450 FPS -- roughly the same weight as a 9mm but 25% faster . In a 20" barrel carbine this load gets 2000 FPS-- probably 4d+1 or so. Thats a hella lot of power.

Not bad...I get 4d.

[DouglasCole]

Originally Posted by Sadurian Mike

Then there are people who die from arrows.... Sometimes, anecdotal evidence of survival and death don't make good analysis for how powerful a round is. Muzzle velocity is directly related to the power of the round, as it is often the ballistic shock that kills rather than the actual bullet damaging flesh.

This should be "there has never been any proof that ballistic shock even exists as a wounding mechanism; and should never be referenced with respect to death by gunshot wounds."

The primary incapacitation methods are (1) brain and spinal cord damage; (2) tissue destruction that leads to massive and rapid blood loss, (3) structural bone damage that leads to inability to move, and occasionally (4) temporary expansion cavity (mostly present in high velocity rifles) can press up against nerve clusters and cause a short seizure-like behavior.

That's about it. "Ballistic shock" is pretty much a myth, and most tissue is very, very resistant to true shock waves.

The temporary expansion cavity thing is really interesting, in a squicky way. The temp cavity isn't worth much unless you hit inelastic tissue or you get fragmentation. BUT, with some larger rounds, like the 7.62x51mm NATO round, the temp cavity can be the size of a volleyball. This can press up against the spine, sending random nerve pulses everywhere. This can cause knockdown and a few seconds of incapacitation even if the overall wound is not incapacitating by (1-3) factors above.

[DouglasCole]

Originally Posted by Sadurian Mike

Poor science? Okaaaaay. I guess you don't believe in it. No matter, plenty of scientists do. I am not suggesting pistol rounds kill through ballistic shock, btw.

Many firearms enthusiasts do; no scientists do. Read Fackler.

No, I'm not joking. The magnum round was specifically developed to increase the stopping penetrating and power of pistol cartridges. Bleeding only kills if the round misses causing shock, normally either through hitting an organ or major blood vessel.

Ah...you're using "shock" to mean "bleeding out." You need to be careful here; shock and shock waves are specific technical terms that have very little to do with incapacitation, despite well known but poorly informed assertions otherwise. One REALLY needs to read the true scientists (MacPhereson, Fackler, Di Maio, although I quibble with some assertions of his) to understand how bullets kill.

Note that this is quite different from "how bullets punch through solid, homogenous objects," and it is THIS quantity that GURPS damage numbers most accurately reflect. The true (and I hate to use this phrase) 'stopping power' of these weapons can only be assessed once you apply the wound channel modifier, which gurps calls "bullet size modifier."

That there are only two steps, {1} and {1.5} means that some artifacts of effectiveness will creep in. The .45ACP in more detailed numbers does 2d{1.5} from a 127mm barrel; the .45GAP, firing a 200gr .45 caliber bullet at 300m/s gets 2d+1{1.5} from a 117mm barrel. The .40S&W should properly get 2d+1{1.2} from a 102mm barrel. or 2d+2{1.2} from the full five inch barrel (like in a Beretta M96). So the .45ACP is 0.6pts of INJURY superior to the 180gr .40S&W, but 2pts worse PENETRATION; this matches reality fairly well. Toss in bullet placement and randomness, and the two will be fairly indistinguishable, again, matching reality - in truth, all handgun bullets are fairly ineffective killers. Thus springs the maxim, "if it's worth shooting, it's worth shooting twice."

Not so actually. There are plenty of tales of 5.56mm not stopping an opponent, but the .45 is still reliably reported as putting the opponent on his behind.

There are plenty of tales either way. The wound cavity of a .223 within its usage regime (larger than 660m/s) is huge, the size of a grapefruit or even occasionally a volleyball. The wound cavity from a .45ACP is...a tube .45" (or .7" if you have a proper JHP) and perhaps a foot deep.

Many (not all) of the issues with the 5.56x45mm rounds has been coming from the Army's habit of issuing very short barrel rifles to the troops, combined with the M855 SAP ammunition and higher rates of barrel twist in the rifles. These bullets do not yaw and fragment as reliably in flesh as the older bullets, and if a .223 doesn't yaw and fragment, you either hit something vital, or you get a .22 caliber hole which doesn't do much. However, with a proper size barrel at engagement ranges up to 150yds, the rifling twist and SAP round don't matter much, and you get a lot of dead bad guys.

It's what it was developed for, after all. 5.56mm is smaller and lighter than large calibre ammo, and the weapon does not need to be as strong and therefore as heavy, but it is not the magic man-stopper.

Neither is the .45ACP, or any other reasonable self-defense or assault rifle cartridge.

That was graphically seen during the Falklands where RM Commandos (almost certainly SBS in fact) using 5.56mm saw opponents keep going, but they stayed down when hit with 7.62mm. If you are saying that 7.62mm is less powerful at the same muzzle velocity... well, call me hightly sceptical.

Comparing a .223 and a .45ACP with a full power battle rifle isn't exactly proper. It's got twice the energy, three times the mass, and a larger cross section than the 5.56x45mm NATO. No one would expect anything less than this round being more effective than the 5.56mm round.

As for a musketball being as effective as modern rounds... again, if you are claiming it is as powerful as a .50 round then I am again highly sceptical. In fact, I would call you entirely wrong and ask where a musket ball was known to penetrate armour plate or even brick walls.

He was quoting the .50AE, not the .50BMG. The .50AE from the Desert Eagle gun does about 4d in GURPS (the ,500S&W about 6d) which favorably compares to musket balls in penetration, although the spherical lead musket ball probably qualifies for an armor divisor of about (0.8).

[DouglasCole]

Originally Posted by Apache

WTF?!?!

.40 S&W is NOT superior to .45 (either ACP or GAP).

As for 10mm.....its a popular round. Many people use it. I almost went 10mm myself....definitely more lethal than .45 ACP.

Again, this is an artifact of the GURPS system.

.40S&W is, very definitely, a better PENETRATOR than .45ACP. .45GAP, much less so, as all things being equal (meaning same launch platform), it's a faster round.

Here are the stats used, I believe, to calculate the relative damages:

From a 5" barrel:

.45ACP: 230gr at 245m/s (805fps): 2d{1.5} gets pi+ in GURPS
.45GAP: 200gr at 305m/s (1000fps) 2d+1{1.5} gets pi+ in GURPS
.40S&W: 180gr at 313.5m/s (1030fps): 2d+2{1.2} gets pi+ in GURPS

I don't think anyone would argue that the last two rounds, which differ by only 25J in energy, aren't well reflected as better penetrators than the 2d .45ACP. The math works out that the .40 ekes over the line to 2d+2 by just a little tiny bit, so if it really bugs you, make it 2d+1 for most weapons with 3-5" barrels.

the real issue is that everything from .40 on up in reasonable handgun calibers gets pi+, while in reality, the cross-sectional area of the .45 is quite a bit larger than the .40.

so unless you want to deal with calculators at the gaming table, the .40 (and even more so the 10mm) at TL8 is simply a better round than the .45ACP from TL6.

In fact, if we didn't have all the real numbers in front of us, and a hundred year history of people asserting the glory of the .45ACP over the hydrogen bomb in terms of effectiveness (I kid, I kid), we'd be mad as hell that a TL8 pistol gets LESS damage and effectiveness than a TL6 one! Can you imagine the howls of outrage if that would have showed up in Ultra Tech?

"What do you mean that the TL11 Murtilizer does LESS damage than the TL9 Murtilizer?! What were they DOING for those tech levels?"

[dukofdeth]

I didn't save the link, but some time ago, while looking for ways to calculate damage from MV, barrel length and bullet size, I came across an article (found via Google) that cited several studies that stronly suggested that ballistic shock (ie: from the bullet shock wave) was not a significant factor in the increased destructiveness of high powered rifle rounds. What is, however, is bullet re-orientation. Apparently, while bullets travel point first through mediums like air, when they hit something like flesh, they re-orient themselves to travel butt-first. In other words, the bullets spend a portion of their time moving through flesh sideways

[Anthony]

Originally Posted by DouglasCole

The primary incapacitation methods are (1) brain and spinal cord damage; (2) tissue destruction that leads to massive and rapid blood loss, (3) structural bone damage that leads to inability to move, and occasionally (4) temporary expansion cavity (mostly present in high velocity rifles) can press up against nerve clusters and cause a short seizure-like behavior.

You left out the most important: psychological. To quote:

Originally Posted by Handgun Wounding Factors and Effectiveness

Psychological factors are probably the most important relative to achieving rapid incapacitation from a gunshot wound to the torso. Awareness of the injury (often delayed by the suppression of pain); fear of injury, death, blood, or pain; intimidation by the weapon or the act of being shot; preconceived notions of what people do when they are shot; or the simple desire to quit can all lead to rapid incapacitation even from minor wounds. However, psychological factors are also the primary cause of incapacitation failures.

This suggests a realistic (if minor) advantage to a weapon with a big, obvious muzzle flash.

[DouglasCole]

Originally Posted by Anthony

You left out the most important: psychological. To quote:

This suggests a realistic (if minor) advantage to a weapon with a big, obvious muzzle flash.

You are correct, in overall statement; I left out the "primary incapacitation results from bullet damage.." thinking it not necessary to address the point.

Guidelines for bonuses to Intimidation and whatnot would be welcome, but not really appropriate to a discussion of whether the stats of the various GURPS weapons are either an exact match, a playable abstraction with some regrettable artifacts, or flat wrong. In many cases the match is excellent; in almost all others, you have either playable abstraction, or what would otherwise be an exact match but nudged in funny ways due to rounding conventions.

[Fred Brackin]

Originally Posted by DouglasCole

The primary incapacitation methods are (1) brain and spinal cord damage; (2) tissue destruction that leads to massive and rapid blood loss, (3) structural bone damage that leads to inability to move, and occasionally (4) temporary expansion cavity (mostly present in high velocity rifles) can press up against nerve clusters and cause a short seizure-like behavior.

Technically there might be one more. That;s when the size of the temporary cavity exceeds the size of the torso and the target explodes.

Primarily seen in things the size of prairie dogs but I suppose it could be scaled up. A 20mm frangible bullet at over 4000 fps seems about right for a human-sized target.

Fred Brackin