Submarines and their Weapons - Aircraft of World War II

ARTILLERY
1945. The projectile was the forerunner of the FSDS
(fin-stabilised, discarding sabot) round, now in common
use. The credit for the original idea is usually
accorded to a French gun designer, Edgar Brandt, better
known for the infantry mortars he developed; in
the 1930s he produced a very effective 105mm/75mm
projectile, which had very superior performance
when fired from a 105mm gun with a standard charge.
THE'CROSS-CHANNEL GUN
Meanwhile, Krupp's engineers were also working on
a 'brute force' solution to firing a projectile out to
8()km (50 miles) or more by a simple process of refining
the original design of the Paris Gun. The result
was the K12, in 21cm calibre, which used the same
rifling and shell-seating method as the K5, with the
addition of a composite copper/asbestos/graphite
band to improve its sealing within the tube and maximise
the effect of the propeliant charge. It was hoped
that the use of soft iron splines rather than simple lugs
would both cause them, and not the hardened molybnedum-steel
of the barrel, to wear, and also spread the
load of rotational acceleration, thus prolonging barrel
life even in the presence of an abnormally large pro-
116
peliant charge. The first barrel was proofed in 1937
and the first complete gun, the K12(V), was tested in
1938 and declared serviceable in 1939. It fired a
107.5kg (2371b) shell out to a maximum range of
115km (71.5 miles) and the Army declared itself satisfied,
for it was a greater distance than the Navy had
achieved with the Paris Gun. Beating that record
seems to have been a major incentive. However, it
was less than perfect in operation. It had to be jacked
up by Im (3.3ft) into its firing position, so as to allow
extra space for recoil, and then returned to the lower
position for loading. Krupp was asked to devise an
alternative mounting sub-frame and so produced a
modified gun with strengthened hydraulic buffers as
the K12 (N) in the summer of 1940. No more were
ever constructed.
Mounting the gun presented problems of its own.
To begin with, its barrel was 157 calibres long, well
over three times the length of comparable naval guns,
more than 33m (108ft) from breech to muzzle. This
Below: Two K5s were in action against Allied forces
contained on the beachhead at Anzio for four months in
1944. One was captured and shipped back to the USA.