g. Charge, Demolition:
(1) Description. The 40-pound cratering dem-
olition charge is a watertight cylindrical metal
container with approximately 30 pounds of an
ammonium nitrate based explosive and a TNT
based explosive booster of approximately 10
pounds in the center portion next to the prim-
ing tunnels. Two priming tunnels are attached
to the outside of the container, midway between
the ends. One tunnel serves as a cap well for
priming the block demolition charge with an
electric or nonelectric military blasting cap.
The other tunnel is for priming with detonating
cord passed through the tunnel and knotted at
the end. A cleat between the tunnels secures
time blasting fuse electrical firing wire or deto-
nating cord in place. A metal ring is provided
on the top of the container for lowering the
charge into the hole.
The ammonium nitrate based
explosive has a relatively low detonating veloc-
ity and is therefore unsuitable for cutting and
However, the blast
effect, which is related to pressure of gases pro-
duced, gives it a pushing or heaving effect
which makes it suited for cratering and ditch-
ing operations, The 40-pound cratering block
demolition charge has been designed as a stan-
dard cratering charge. Because of the large
amount of explosive in convenient form, it may
also be used in destroying buildings and fortifica-
h. Charge, Demolition: 40-pound, Cratering (New
(3) Advantages. The size and shape of the
charge make it ideal for cratering operations.
It is very inexpensive to produce compared to
There are three different, new versions
(4) Limitations. Ammonium nitrate readily
of the 40-pound cratering charge. They
absorbs moisture thereby becoming more diffi-
are differentiated by their NSN's, mark-
cult to initiate and less effective. It is not
ings, and the priming methods required:
possible to detonate wet ammonium nitrate.
To insure detonation, the metal containers
must be inspected for any evidence of water
250-6029) Primarily Navy/Marine
damage, and all charges placed in wet or damp
Corps issue. Requires priming on
boreholes should be detonated as soon as pos-
top with a military blasting cap or a
sible. Ammonium nitrate cratering charges
10-turn Uli knot of detonating cord.
should be dual primed.
Second Generation: (NSN 1375-01-
378-9669) Primarily Army issue.
Requires dual, side priming with dem-
olition charges, Markings tell how
and where to prime.
Third Generation: (NSN 1375-01-
TBD) All services in 1994 or later.
Requires only top priming with a sin-
gle pass of detonating cord and an
overhand knot and has two detonat-
ing cord tunnels for dual priming.