JP>-> JP> -> Don't know--though the total energy is equal to heavier, slowe
JP>-> JP> -> rounds,
JP>-> JP>
JP>-> JP> Velocity is EVERTHING when it comes to defeating body armor.
JP>->
JP>-> No.  Bullet deformation is what allows Kevlar body armor to stop
JP>-> bullets.  That's why Eastern-bloc .380 ammo with sintered-iron core
JP>-> will go through a vest despite low velocity.
JP>I don't want to pretend to expertise I don't have.  I haven't
JP>actually conducted any tests, personally.
JP>Let me just note that with the two glasser rounds I was referring to,
JP>the bullets were identical, only the velocity was different.
JP>A cast lead bullet, loaded into a rifle round and fired at rifle
JP>velocities, will also defeat these vests, I believe, despite being
JP>softer than these iron core bullets you mentioned.
When I was in the Army, I was tasked to evaluate adopting "teflon
coated" ammo to penetrate enemy soft armor.  I got two reports -- one
from the Justice Department, and the other from the Treasury Department
-- on teflon coated ammo.  They concluded teflon ammo does NOT enhance
the ability to penetrate a vest.
Try this -- shoot a .22 at a sheet of paper.  Look at the bullet hole.
It will have a "puckered" appearance, with the pucker on the back side.
Put your finger to the back side of the paper and smooth out the pucker.
You now see a tiny, irregular hole, much smaller than a .22.  This hole
is surrounded by a black mark (called a "scuff collar") and has tears
radiating from it.
This tells you HOW the bullet penetrated the paper.  At the instant the
bullet touched the paper, only the nose exerted pressure. The paper
stretched slightly, then the tensile strength of the fibers was
overcome, and the irregular hole was formed.  The nose of the bullet
entered the small hole, and the "shoulders" of the bullet made the tears
as they enlarged the hole, and left the scuff collar as they brushed the
paper around the hole.
The two key elements of penetration were stretch and tensile strength.
Kevlar has virtually zero stretch and a very high tensile strength.
When the bullet hits the vest, the threads of the vest neither stretch
nor break.  The bullet tries to carry these threads with it.
The problem is, the threads are part of a woven fabric -- so the whole
fabric is carried along.  And because the vest goes completely around
the body, the bullet can't pull the whole vest along.
In one case that I know of, a .44 magnum bullet and a loose vest
resulted in the bullet carrying the fabric between two ribs -- and
stopping there.  The skin wasn't broken, but the bullet -- wrapped in
kevlar -- was INSIDE the ribs.  They had to cut the vest, leaving a
ragged swatch of fabric sticking out from between the ribs, then break
the ribs to get the bullet out.
Now, none of this has anything to do with the material the bullet is mde
out of.  The bullet can be made of pure lead, or sintered tungsten.  It
makes no difference.  To penetrate a kevlar vest, you need velocity.
There is one exception to this -- kevlar cannot resist a sharp edge.  A
knife will cut right through a vest, just like through any other cloth.
Cyclone bullets take advantage of this -- the Cyclone bullet is a
thick-walled tube of beryllium copper (or other hard metal).  The edges
of the forepart of the tube are sharpened -- so the bullet resembles a
truncated cone on a cylinder.
A mushroom-shaped plug is fitted in the bullet, plugging the central
channel.  When the bullet leaves the muzzle, the plug drops off and the
tublar, sharp-edged bullet cuts through vests.
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