| From: | Paul J. Adam Paul@********.demon.co.uk |
|---|---|
| Subject: | Armor Penetration |
| Date: | Fri, 26 Feb 1999 22:56:03 +0000 |
<acgetchell@*******.edu> writes
>When considering the damage potential of a weapon, there are three main
>criteria:
>
>Kinetic energy, as it relates to the amount of joules the weapon can
>deliver to the target. This relates directly to tissue damage.
To an extent, but not quite "directly". As Dr Fackler says, when a
meteorite comes through your roof, you don't care how much "energy it
transferred", you care how big a hole it made.
>Momentum, which provides knockdown capability but, more importantly,
>preserves kinetic energy through the trajectory of the round.
>
>And physical characteristics of the bullet; ie diameter, elasticity,
>aerodynamics (both in-flight and within the target). This affects both
>energy retention in flight and energy delivery to the target in terms of
>wound channel and tissue damage.
>
>Dr. Martin Fackler of the Wound Ballistics Lab in Maryland has published
>that "damage" is primarily a function of kinetic energy.
To an extent. More precisely, that a round needs both adequate kinetic
energy and a means to convert that into damaged body tissue.
>Also, "hydrostatic
>shock" does not add significantly to trauma caused by round impact, with
>the sole exception of rigidly contained areas of the body (ie the skull).
Or the liver, or fluid-filled organs such as the stomach after a meal...
but Fackler's scathing about the idolatry of "hydrostatic shock" and
"temporary cavity" as wounding mechanisms.
>Finally, as far as the question of barrel length, note that there is an
>optimal length for each round wherein the gunpowder deflagration imparts
>maximum energy. Shorter barrels lose some of this energy transfer, while
>longer barrels reduce the total energy with friction. An edition of Guns
>and Ammo ran several tests with various length barrels and a ballistics
>setup to demonstrate this point.
I recall this. I also recall comments about how, due to internal
ballisic considerations, a 3"-barreled 9mm Parabellum revolver could
achieve more hitting power than an almost identical weapon chambered for
.357 Magnum. While if you double the barrel the Magnum has the
advantage, that's not an option for most backup pieces.
>As such, Shadowrun miserably fails to tie in these factors in any sort of
>meaningful way. For example, let's put the standard rifle in the .303 class
>of weapon. There are two damage levels, 7S and 10S, which we'll assume
>relate to barrel length (carbine and rifle respectively).
I figured it was two different calibres, myself; say, .308 and .338, or
something similar.
But then, FASA never made much sense on the issue. If the AK-97 even
vaguely resembles the AK-74, then the AK-97 Carbine equates to the AKSU
of today; and that weapon is both more lethal and more penetrative than
any 9mm/.40cal SMG of today. Yet it's _less_ lethal than Shadowrun SMGs?
The SR2 firearms damage rules were playable, especially as they related
to shotguns / assault rifles / pistols. They weren't _realistic_, but
then being told "They've got automatic weapons and they outnumber you
five to one. You've got a 9mm pistol. You die. I can't be bothered
rolling dice when it's so obvious what will happen." isn't fun to play.
>Now lets take the Barret sniper rifle, .50 caliber weapon, 14D.
From "Elven Fire", the "sniper rifle" is a .655 subsonic, which makes
more sense in some ways for such a high damage code (though offhand I'd
make it 10D myself, and have HMGs at 15S base damage)
>We may
>attest that the increase is due to higher velocity, heavier round, and a
>longer barrel. However (and I don't have any ballistics tables on me), I'm
>not sure that the velocity difference between a .303 and .50 is large (by
>which I mean it is within a factor of 2), but we'll leave that open.
Assuming you mean .303 Lee-Enfield, then the "standard" ballistic table
entry is for a 180-grain bullet at 2460 feet per second.
.50 Browning Machine Gun is about 670 grains of bullet, at 2910 feet per
second.
>Compared with a Barrett, an M2 .50 HMG lacks only barrel length and
>possibly, improved bullet composition.
Why? If it feeds in a Barrett, it'll feed in a M2HB heavy machine gun.
Indeed, the favoured real-world load for the Barrett rifles - the
Raufoss multipurpose - was designed for and is widely used in the HMG,
and was later adopted for the rifles.
>When I proposed the OICW Block 4, I was extremely conservative in the
>effects of ETC propellant. Imagine an assault rifle firing rounds at 2000
>meters per second or so. Using the examples that have been given to us in
>FOF and elsewhere, how would one model a doubling of kinetic energy?
16M damage from an assault weapon, perhaps?
--
Paul J. Adam
