Re: Weapons (was Re: transparent aluminum)

From: James Rogers (
Date: Wed Feb 27 2002 - 00:02:48 MST

On 2/26/02 5:19 PM, "Mike Lorrey" <> wrote:
>> Contrary to what Michael Lorrey stated, they will NOT stop AP (armor
>> penetrating) rifle bullets.
> If this is so, then why is it that the same material is used to stop
> anti-tank artillery rounds?

Irrelevant, and inaccurate in any case (at least as it applies to U.S. armor
systems, which are none too shabby). Modern body armor will only stop
"penetration enhanced" rifle bullets (what they sell to civilians as "AP").
These bullets are designed such that they can penetrate a layer of hard
material (masonry, a car door, etc.) and still be in sufficiently good shape
to penetrate a person wearing flak armor. Ordinary lead bullets
disintegrate upon hitting the first hard material, which means that many
times you can't shoot at someone using cinder blocks as cover; the bullet
may make it, but it will be in such poor condition that it won't produce an
effective wound. Enhanced penetration bullets were designed to deny certain
kinds of cover while still nominally behaving like ordinary bullets. They
still have a lead core, but have a mild steel tip that offers some
protection for the lead core and allows the bullet to still be mostly
effective after penetrating a layer of hard material.

Real AP is a completely different animal, as it radically modifies the
sectional density and sectional energy profile to vastly increase the
penetration. The kinds of armor required to counteract the physics involved
would be too heavy to be usable as body armor.

And while some heavy armor systems use ceramic composites, it isn't the same
kind used in body armor. In fact, most of the advanced composite armor that
I can think of is designed specifically to counter shaped-charge type
anti-armor weapons and not kinetic energy anti-armor weapons, which is what
we are talking about here. Body armor systems are constrained by weight and
size as a primary factor, whereas these are not issues on a tank. It
therefore makes sense that the design parameters are substantially different
both in the practical logistical aspects and the types of armor penetration
modes they have to contend with, so it shouldn't be surprising that the
apparent relationship between tank armor and body armor is mostly

-James Rogers

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