May 24,2008:
The demise of al Qaeda in Iraq,
and the shift to fighting Iranian backed Shia militias, has led to greater use
ofIranian made explosively formed
penetrator (EFP) weapons. Last year, about five percent of the Coalition combat
deaths in Iraq, and about eleven percent of those killed by roadside bombs,
were because of EFPs. This year, that percentage has increased, but not as much
as expected, because of extra armor added to the sides of MRAPs (Mine Resistant
Ambush Protected) vehicles.
The EFP is
nasty because it can penetrate the armor on just about anything but an M-1
tank.An EFP is a precision weapon, a
cylindrical device, that is often described as similar to a coffee can. But the
cylinder metal must be thicker. You fill about 60 percent of the "coffee can"
with explosives (C4, also known as plastique will do). Then you insert a
detonator on the closed end of the "coffee can" and a concave copper plug that
is pushed into the plastic explosive. The tricky part here is that the depth of
the concave copper part, and the thickness of the copper, have to be just
right. It requires someone expert at math and the chemistry of explosives to
make those calculations. You can make a mould for casting the copper plug, but
you must make sure you get the thickness just right. The more precisely the
copper plug is made, and the EFP assembled, the more armor the device will
penetrate, and the more damage it will do inside the target vehicle.
By adding
another two tons of side armor to an MRAP, most EFPs can be defeated, usually
with fatal consequences to the attacker, who is quickly fired on by the troops
in the MRAP, and other vehicles in the convoy. There are about 3,000 MRAPs in
Iraq, and only about ten percent have the additional side armor. These up-armored
models are used in areas most likely to encounter EFP attacks, and have
contributed to reducing EFP casualties nearly 20 percent, even as EFP attacks
have climbed nearly 50 percent in the last few months. The greater use of MRAPs
has cut roadside bomb casualties by 40 percent this year, even though such
attacks are up about ten percent.
Combat
commanders believe that over a hundred American lives have been saved this year
because of MRAP use, and the troops seem to agree. Morale is up now that
roadside bombs, particularly EFPs, are less of a threat. During the first four
months of this year, 162 U.S. troops were killed in Iraq.
