106 SHOOTING SPORTS MAGAZINE
Propellants have come a long way in the last 200-years as can be seen!THEIR DARK MATERIALS!
Wheelwrite takes a fresh look at the fuels that power our ammo –
single, double and triple base ‘low explosive’ propellants
G
etting tecky they are called energetic
materials. Let’s briefl y look at the
steps that moved us from smoky
gunpowder (aka black powder) to the
diverse spectrum of almost 200 designs of
small arms propellant on the market today.NITRATED WOOD OR
COTTON PRODUCTS
We have to begin by recognising the
signifi cant difference between detonation
and defl agration. In simple terms,
detonation is an ‘all at once’ release of
energy, a true explosion. Defl agration is
also a self-contained chemical reaction
(requiring no external oxygen or other
chemical input), but here the rate of
reaction is related to containment pressure.
Modern ‘energetic’ chemical compounds
really started with the accidental discovery
of nitrocellulose in 1846. The early,
undeveloped ‘explosive’ form better known
as guncotton. It was remarkably smokeless
but, as the original discoverer observed, it
detonated. It was just a year later that the
invention of nitroglycerine was recorded.
Trouble was, when triggered it also
detonated. It would be another couple of
decades before a practical, defl agrating
propellant material became available. Again,
the base of the material was nitrated
cellulose but the chemistry was better
controlled. It was called Schultze Powder.AIRBAG DETONATES,
CARTRIDGE DEFLAGRATES
The1880’s saw a fl urry of new nitrated
cotton propellants that were safer and more
or less stable! The fi rst, in 1882 was EC
Powder. It was a UK development with
excessive pressure sensitivity, making best
suited to low pressure shotgun cartridge
use. A couple of years later the fi rst fl ake
small arms propellant was developed by
French chemist Paul Vieille, to distinguish it
from BLACK powder it was called WHITE
powder, Poudre Blanche or Poudre B.
During its lifetime Poudre B was
re-engineered many times, not least by theproducts of the nitrated cellulose procedure.
While it is not fl ammable it has an extreme
detonation velocity, justifying it’s thoroughly
modern application as an air bag propellant!AMERICA – LATE AS USUAL
It was the turn of 1890 before the fi rst
serious Colonial production began, based
around the European guncotton
developments. An established black powder
miller, the Anglo American Explosives
Company took the lead. However, the US
Army really kick-started further
developments when they issued a
smokeless propellant specifi cation for their
new service rifl e, the .30-40 Krag. A new
product called Ruby, made by the newly
formed Leonard Smokeless Powder
Company was selected. Leonard were later
to become the American Smokeless Powder
Company (ASPC), working with fi nancial and
technical help from Lafl in & Rand to morph
Ruby into the long-lived WA .30 Cal Powder.RELOADING
infamous German Krupp organisation. In
1887 it was the turn of Alfred Nobel with his
double based Ballistite, a mix of
nitroglycerine and nitrocellulose. Rather
dangerously, the stabilising, wetting agent
was Camphor which, over time evaporated
to leave an unstable explosive compound. It
fell to a Brit team to re-engineer Ballistite by
replacing Camphor with Acetone. It was to
become the fi rst truly modern defl agrating
propellant, the double based extruded rod
known as Cordite.
A 1930’s property changing
development of the base Cordite recipe saw
the inclusion of nitroguanidine (aka Picrite),
creating an early triple base propellant.
Given that double base propellants burn
hotter than single base it is hard to
comprehend that this triple base recipe was
cooler burning - although not ideally suited
to use in small arms. It was more commonly
used in artillery applications. Ironically, a
form of nitroguanidine was one of the earlyNo it’s not spaghetti but Cordite in a 303 cartridge Neutral deflagration - the bore gets bigger as
the outside shrinks