Ammonpulver (AP).

AP was developed in the late 1880s as a replacement for black powder. It
is an intimate
mixture of 85 percent ammonium nitrate and 15 percent char-
coal. It was used by Germany and
Austria as an artillery propellant until
nitrocellulose-based powders became commonly
available. It was extremly
powerful, being on a par with double-based powders containing 30
percent
nitroglycerine, and was virtually smokeless and flashless.
Unfortunately, AP
had two drawbacks that made it undesirable as a prop-
ellant. First, since it was based on AN
it was extremly hygroscopic, and
second, when it was heated to moderate temperatures
(32.1øC), a change in
the crystalline structure occured, causing the powder grains to
crumble.
This would cause a drastic increase in the chamber pressure of guns using
this
propellant, often causing burst tubes.
Since we will be using AP as a bomb filler, however,
this becomes a pos-
itive asset. It is very cheap to make – about thirty to fort cents a pound
-
and is quite insensitive to friction. It is, however, much harder to ignite
than
black powder, so a booster consisting of a few grams of a more sensit-
ive compound such as
potassium chlorate/sugar or black powder must be used.
As a filler for pipe bombs or related
items it is without peer.

Preparation:
1) Grind the AN prills in a blender until
finely powdered. Sift
through a flour sifter, spread out in a shallow pan, and dry
for
fifteen to twenty minutes in a warm oven. Pour into an
airtight jar and seal.
2)
Pulverize the charcoal in a heavy cloth bag, then grind in the
blender. Sift.
3) Pour 85
percent AN and 15 percent charcoal, by weight, into a
rock or case tumbler and add a handful
of lead balls. Tumble
for several hours. Open and inspect. The contents should be a

fine, dark gray powder. It may be necessary to tumble for an
additional lenth of time.

AP must be as finely powdered as sifted flour for optimum
performance. The hardness of the
charcoal is the major obstacle
to achieving this state. I find it simpler to buy powdered /> charcoal (325 mesh) at a chemical supply house as opposed to
powdering barbecue briquettes.
This form of charcoal may also
be found at companies catering to the sign-painting
industry.
Ask for "pounce powder". Both the separate ingredients and the

completed powder must be scrupulously protected from moisture
during all operations. Any
device containing AP should be
painted with a sealer as a precautionary measure.

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