If the bullet doesn't function properly in the layered denim tests, that probably means it won't function properly in a large number of other situations where the physics of the impact do not match the simple gelatin block tests -- such as when the bullet goes through bone before penetrating much tissue, etc.

A 165gr .40 S&W has greater sectional density than a 200gr .45 ACP, and .40 180gr the same as .45 230gr. Though you're still right that more massive bullets will be less upset about light cover, all other things being equal.

Anything other than dedicated armor piercing rounds for any of the discussed calibers is going to be stopped by just about any kind of body armor widely used today, so this isn't a real issue. If it was, you certainly shouldn't endorse .45 ACP, which is far worse at penetrating body armor than the 9x19mm.

I am quite aware of that. That's why I mentioned PKMs. Any serious group of insurgents in Iraq or Afganistan or armed mob in Africa has them. GPMGs in that caliber still arm a whole lot of national militaries around the world.

I think the orig poster was saying that since the PKM is the GPMG of the AK family, you are likely to find PKM machine guns in the same armies you find AK-series assault rifles.

Edit: Heh, and the OP beat me to the clarification... Rock on, AE!

The .45 was designed well before body armor was a concern. It was meant to hit an unarmored man hard enough to knock him down as the Army issue .38 was deficient in that regard.

The .40 was intended to be a compromise between the 9mm and .45. It seems to do well enough and I have one myself, though I haven't fired in a while and never at another person.

As body armor becomes more common, the 9mm and other rounds might come back in to favor since they would have a better chance of getting through the armor. Then again, maybe not. To really stand a chance against armor, you'd need a rifle, though a shotgun slug could cause blunt trauma through soft armor, but I haven't seen any studies on that.

You could always aim for the legs though.

Any particular reason you've reached these conclusions? It seems a bullet halfway in size, mass and velocity between a 9x19mm and a .45 ACP will be halfway between them both when considering deflection from penetration of cover and body armor backface signature injuries.

If you've got better data on BSIs than what can be collected from the Kevlar Survivors' Club, I'm very interested in seeing it. The stuff there doesn't support the idea that .45 ACP tends to cause more significant blunt injuries through armor, and the fact that .45 ACP loads make much less of an impression than 9x19mm through armor on the backing clay used in testing armor doesn't help either.

Your actually on the money here. There are two schools of thought on the defeating of personal armor making the rounds at this time.

The first school is best evidenced by the 5.7x28mm cartridge developed by FN for use in the P90 SMG and Five-seveN pistol, and the 4.6x30mm used by tthe new MP-7 and UCP by H&K.

These are high velocity low mass projectiles, usually being composed of copper jacketed aluminum. The mechanics of their penetration are complex, but well documented on the web. To my limeted understanding, the round basically applies kinetic energy faster than the armor can disperse it, allowing it to push through and penetrate.

A bastard cousin of these rounds would be the .224 BOZ, which is disturbingly effective versus hard armors as well (can shoot through APC armor!)


The other approach to defeating armor is the high-mass medium/slow velocity projectile that just dumps so much kinetic energy againse the armor that it overwhelms it. While penetration isn't likely, its not very necessary as anything on the other side of the armor is usually pulped by the impact anyways. Examples of this round would be the .50 Beowulf, .458 SOCOM, and believe it or not even .50AE if fired from a carbine length barrel.

I'm trying to find the info, but it may take some time. I'll post it as soon as I do.

So poor performance against clothing isn't a concern, but poor performance against car doors and automotive glass is? I mean, I don't know enough to have a position, but that seems sorta… odd.

As for "wounding through armor", I'm pretty sure ~500 joules/~16.8 kg*m/s isn't going to be doing that on any consistent basis.

~J

I've seen those guns you mention. However, there doesn't seem to be much of a market for them yet. The big problem as I can tell is that while they penetrate armor well, they don't have much stopping power. I know that was a problem with the 5.7x28.

Tank rounds get their pentration from velocity and materials. The harder the material compared to the target material, the better chance it has of getting through. It is pretty much the same with personal ammo too. A steel core bullet will penetrate more than a jacketed lead bullet of the same caliber. The longer the bullet can go without deforming or breaking up when hitting body armor, the better chance it has of getting through. The high velocity and shape of those bullets you mentioned allow it to get through the armor.

But we are back to the root problem. Bullets that are good at piercing armor aren't as good at stopping unarmored targets. If we were using a 7.62 round, this wouldn't be much of an issue. I used to have some .30-06 saboted rounds called Accelerators or something like that. They had much higher velocity than a standard full-sized round. A 7.62 would be larger enough so have something like that developed for it against armored enemies, while another could be for unarmored enemy. Different bullets but same gun. 5.56 is too small to do that.

The US military and their M995 5.56x45mm WC core armor piercing round beg to differ. Serious armor piercing ammunition designs exist for all major military rifle calibers.

I meant that the 5.56 is too small to make an effective sabot round for it, like the one for the .30-06. There were experiments with a saboted flechette for the 5.56, but it didn't work out too well.

Two different topics. We were discussing the performance issues (accross all calibers) with Hydra-Shock ammunition against heavily clothed targets. The nose of the rounds tend to get plugged up with cloth and performance drops to roughly that of an FMJ round.

The .40 vs car issue was a seperate matter that gets into some oddities it has ballistically. My physics knowledge is good, but rusty, but it basically comes down to the shape and velocity aren't optimal for hard surface penetration. This is acutally a good thing from a law-enforcement perspective, as it significantly lowers the chances of structural over-penetration by missed shots.

Besides, I think they are teaching cops to use shotguns/carbines vs. cars now anyways.

Hehehe check these puppies out:

http://en.wikipedia.org/wiki/HEIAP

That is a nasty, nasty, nasty little projectile.

Judging by the fact that the M948 SLAP for the 7.62x51mm NATO never caught on but the M993 did, I'd say these are too small for sabots too. At least as far as penetrating armor goes, that is -- the Swedish and perhaps others are apparently working with 7.62x51mm sabot rounds for sniper rifles, to get flatter trajectory and less wind shift.

Ive heard about doing this with .50's with great success. I want to remember seing the sabots for fitting a variety of smaller caliber projectiles into .50BMG casings.

The .338 Lapua Magnum is also pretty good at anti-armor work, but it's large enough to almost be an anti-material round itself.

That was what the .30-06 round I mentioned was for: greater speed with flatter trajectory. It succeeded at that, but was greatly affected by the wind because the projectile was rather light.

Here you go.

It was 1905, actually. 102 years old now.

It was 1902, actually. 105 years old. The downside of lifting text from Wikipedia is that it isn't always correct. (The Luger/Parabellum pistol was patented in 1898. It wasn't chambered in what we know as the 9x19mm Parabellum until 1902.)

Image lifted from my site (which I lifted from barrettrifles.com).

There was a bunch of other stuff, but as usual, Aus has pretty well taken care of it.

Yeah, but then you wouldn't hear a voice go, "HEADSHOT! MUH-MUH-MUH-MONSTERKILL!"



Jokes aside, and on the subject of gaming, I'm actually working on a Fallout 2 mod where I convert most of the Small Guns into WWII and Korean War era weapons, as I feel like that would go better with the flavor of Fallout than P90s and 10mm handguns would, which strike me as being more contemporary than what is suggested by the Fallout artwork.

If I had to make comparative videogame statistics for performance versus armor of .45 ACP and 9x19 Parabellum, would you guys have any general pointers or hints? Fallout isn't really a realistic game but I figure if I go for some verisimilitude it would only help the enjoyment of the game.

Partly true, the Luger pistol was patented in 1898 ("late 1890's" as I said) and production models were first introduced with a 7.65 mm cartridge. However, a trip to the local library will reveal that DWM had be experimenting with the 9mm cartridge from the beginning. Sadly, I am not in a postion to provide proper citation, but it is out there.

But, we've already gotten this thread faaar offf topic anyway. Thus, I will enlighten our debate with this motivational message:

.50 BMG

Not to get into a hair-splitting contest, but the text you posted said nothing about the Luger pistol. While it is possible that Luger may have been experimenting with 9mm cartridges from the beginning (the evidence I have seen suggests otherwise; the 9mm cartridge wasn't experimented with until 1901, after the Swiss adopted the 7.65mm Model 1900 and several other countries, including the US, rejected that model), what we now know as the 9x19mm Parabellum cartridge was not finalized until the Model 1902 was submitted to the British for consideration in that year. A 9mm Parabellum version of the Luger pistol wasn't adopted by any military until 1904 (German Navy).

I suggest reading Military Small Arms of the 20th Century by Ian Hogg and John Weeks (7th Edition, pp. 39-42) or Cartridges of the World by Frank Barnes (9th Edition, p. 273).

These are the parameters I can adjust:

1.) Damage roll (random number between a minimum and maximum value)
2.) % reduction on the to-hit penalty caused by armor class
3.) % of armor's damage reduction stat negated by the cartridge

To make things a little bit more complicated, the cartridges I have to adjust in relation to one another are .45 JHP, .45 FMJ, 9x9mm ball, and 9x9mm FMJ. I suppose later on I'll also have to stat .44 magnum JHP and .44 magnum FMJ.

It's important to remember that the armor in Fallout usually isn't good armor or kevlar, but is rather leather and steel plates cobbled together, so on the whole it shouldn't be super effective at completely eliminating the damage from gunshots, and also I suppose the penetrating difference between 9mm and .45 would be more pronounced than it would be if we were talking about kevlar, zylon, etc.

Right now, I think I've got something to this effect:

a.) .45 JHP gets a 10% penalty on to-hit rolls versus armor, as well a a 15% damage penalty versus armor.
b.) .45 FMJ has no modifiers
c.) 9x19mm ball gets a 5% penalty on to-hit rolls versus armor, as well as a 10% damage penalty versus armor
d.) 9x19mm ball just gets a 5% bonus on to-hit rolls versus armor.


One benchmark to consider is that the game's "uber" scifi round, 2mm EC, has IIRC a 20% bonus to-hit versus armor and a 30% bonus versus damage reduction, or something similar. I plan that the final mod would have 7.62x39, 7.62x51, and .30-.06, but at this time I'm planning to keep them all less effective than 2mm EC, which is supposed to be super and appears at the end of the game. I might consider making 2mm EC better but overall I want to stay away from too much power level inflation.

Unless that 2mm projectile is flung by a railgun, which in this case it is. (Or was it a coil gun?)

I'm not sure about that—there are still a lot of places where I'm sure it wouldn't stop someone, but bone, lung, CNS, heart, throat/neck, femoral artery, etc, while individually smallish targets, add up to a fairly decent-sized effective target area. Of course, it'd probably be best to fire a few rounds at a time, shotgun-style…

~J

eh?

Well, it seems like the purpose would be armor penetration. A frangible round would, at those velocities, break on the first thing it hit, right? That being the outermost layer of armor? Against a lightly-armored human it's going to probably still tear right through, but other weapons can do that. Against a more heavily-armored individual or a vehicle, wouldn't it increase the risk of the round becoming useless before it hits something important?

~J

A bit of a tangent, but ye olde polearms actually relied on this. Your average breastplate would easily deflect a pole hammer, but the shock of impact travelling through your chest you probably kill you, leaving your armor intact and probably in enemy hands waiting to be resized and reused.