 Discarding
sabot projectile. |
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Anti-tank (AT) guns initially used solid steel
armour piercing (AP) rounds which derived
their penetrating power from kinetic energy.
As armour increased in thickness it became
necessary to achieve higher muzzle velocities
in order for a projectile to penetrate, but
steel shot tended to shatter on impact at
velocities upward of about 823 metres (2700
feet) per second. A variety of projectile
types were developed to maximize muzzle velocity
and penetrating power. A soft metal cap was
added first to try to prevent the solid shot
from shattering. It was found that these APC,
or armour piercing, capped, rounds were unstable
in flight, however, and so a ballistic cap
was introduced in APCBC (armour piercing,
capped, ballistic capped) rounds to improve
range and accuracy. The best solution to the
problem was found in armour piercing, discarding
sabot (APDS) rounds, introduced in August
1944. Development had been influenced by Canadian
General A.G.L. McNaughton, a gunner of
the Great War who had commanded the Canadian
Army in Britain until November 1943. APDS
rounds featured a tungsten-carbide core projectile
within a steel jacket that was shed upon leaving
the muzzle. Tungsten-carbide was expensive
to produce, and so heavy that a full-bore
projectile could only be fired at relatively
low muzzle velocities. By using the discarding
jacket, however, the full force of the exploding
propellant was applied to a ballistically-superior
and very dense core, resulting in much higher
muzzle velocities and improved penetrating
power.
Eventually, the upper threshold of development
of kinetic energy anti-tank weapons was reached,
after which guns became too large to be practicable.
Instead of kinetic energy resulting from high
velocity, shaped- or hollow-charge projectiles
relied on explosive chemical energy. When
such a projectile struck, "a fuse detonated
explosive at the end remote from the shaped
cavity at the front of the round and . . .
created a jet of molten metal that would penetrate
armour plate and spray a mass of flame and
melted metal fragments into the interior of
a tank. Hollow charge projectiles were ideal
for low-velocity, hand-held anti-tank weapons"
such as the British
PIAT (Projector, Infantry, Anti-Tank),
the American bazooka, and the German Panzerfaust
and Panzerschreck (Donald E. Graves,
South Albertas: A Canadian Regiment at
War, 1998, p. 365).
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Canada in WWII
Anti-Tank Projectiles
