German taper-bore Guns
SRigoni
principle which imparted a higher velocity to a projectile by firing it down a
tapering barrel. This however had to abandoned after the shortage of tungsten,
which formed the core of the ammunition used, became acute.
I was wondering what happened to these guns. Were they just scrapped, new
barrels fitted to the existing gun carriage or was it possible to re-bore the
guns? It seems like it could potentially have been a huge waste of resources.
Also on this vein, is this principle used today in any weapons or is it
obsolete in the current range of anti-tank weapon systems.
Steven Rigoni
DHeitm8612
>principle which imparted a higher velocity to a projectile by firing it down a
>tapering barrel. This however had to abandoned after the shortage of
tungsten,
>which formed the core of the ammunition used, became acute.
>
>I was wondering what happened to these guns. Were they just scrapped, new
The information I have says that the first taper-bore gun used was the 'Heavy
Anti-tank Rifle 41'
or S.Pz.B. 41 in which the barrel was tapered from 28mm to 21mm. The shot
wasn't big but had good penetrating power at short range.
The second weapon, PAK41, designed appear just in time for the tungsten
shortage to have its effect. This weapon tapered from 42mm to 30mm.
Krupp developed a brilliant taper-bore gun, also called PAK41, in which the
calibre dropped from 75mm to 50mm. This had an overwhelming performance and
would have been one of the finest anti-tank guns of the war, but the tungsten
shortage finished its practicallity. No sense firing projectiles at over 4000
feet second knowing that they would only shatter on impact without a tungsten
core.
No mention of their ultimate fate, I'm sure the weapons were more than likely
scrapped.
Performance of the three weapons below:
Name:______Calibre____Weight in action_____Shell wt._____Muzzle
Vel.____Penetration
S.Pz.B.41.....28mm.......500lb....................0.26lb.........4,595fps.
..........94mm@100m
PAK
41........42mm.......1400lb...................0.75lb.........4,150fps.....
....120mm@100m
PAK
41........75mm.......2990lb...................5.72lb.........3,700fps.....
....209mm@500m
For Comparison PAK43 (88mm):
PAK
43........88mm.......8,150lb..................16.0lb..........3,700fps....
....274mm@500m
The Germans had also started development of a PAW 600 (Panzer Abwehr Werfer) AT
gun which used smooth bore. The 81mm gun used the high-low-pressure system, by
which the projectile (a hollow charge bomb) is seperated from the charge by a
perforated plate. The pressure from the explosion is fed more slowly into the
barrel, so that the barrel need not be so heavy and the gun is more manageable.
Its career was also cut short by the end of the war.
PAW
600......81mm......1,350lb...................5.9lb............1,700fps....
....140mm
Keith Heitmann
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David Thornley
>I was reading recently about the German anti tank guns using a squeeze
>principle which imparted a higher velocity to a projectile by firing it down a
>tapering barrel. This however had to abandoned after the shortage of tungsten,>which formed the core of the ammunition used, became acute.
>
>obsolete in the current range of anti-tank weapon systems.
>
anti-tank abilities by using enhanced ammunition. One problem with
increasing muzzle velocities was that the steel shot might not stand
up to high impact velocity, while some sort of tungsten projectile
would. However, a full-sized tungsten projectile would weigh too much
to be fired with the normal charge, and the loss of velocity would
make it ineffective anyway. The problem to be solved was how to fire
a small tungsten projectile at a high muzzle velocity.
One technique that people had been kicking around for decades was the
subcaliber gun, such as a 12" gun with an 8" bore, so that an 8"
shell would be fired with the powder, and hence the energy, of a 12"
shell. The taper-bore was a variation on this. (I'm not exactly
sure why the subcaliber bore wasn't tried, but I suspect that a
heavy subcaliber projectile in a subcaliber bore might create too
much internal pressure. I do know that supercaliber bores were used
in the British 75mm gun, which was a 6pdr (57mm) bored out.)
in the British 75mm gun, which was a 6pdr (57mm) bored out.)
Anyway, we have a subcaliber tungsten core, which is the part of the
projectile we want headed at the enemy. We have to do something to
fill up the rest of the gun barrel, since otherwise all the propellent
gasses are going to go around the shot and out the barrel.
One technique was to make a light shell around the shot, and keep
that shell intact until impact, so the core would just leave the
shell and continue through the armor. This was the technique
adopted by the Soviets, the Americans, and the Germans (except for
the taper-bore). The big disadvantage was that it not only had the
shell in the bore, but also in flight, which led to increased air
resistance. Since the whole projectile was lighter than the
corresponding steel shot (so it could be fired at a higher velocity),
it lost hitting power pretty fast.
The taper-bore used some of that effect, but squeezed the shell
onto the core at the end of the barrel in the hope that it wouldn't
cause excess drag. This was used by the Germans and the British
(the Littlejohn adapter for the 2pdr). There were several problems
with this. First, some energy would inevitably be lost in the
squeeze. Second, the guns would be relatively expensive to make.
Third, the guns needed special ammunition. An American 76mm gun
could fire standard HE, standard steel AP, or tungsten-core ammo.
A 28/20mm German AT gun was limited to its own special ammo. (Since
the tungsten shortage got increasingly onerous, I would suspect that
the guns were discarded or scrapped, as being of no use.)
The technique used by the British was the discarding sabot idea,
in which the shell went through the bore intact and was discarded
when it left the muzzle, leaving the tungsten core travelling by
itself. This had some problems. The shell ("sabot") discarding
could be uneven, degrading gun accuracy, and the sabot was something
of a danger to infantry in front of the tank. Eventually it won out,
and the main AT round of the M1 main tank is a descendent of these
shot.
--
David H. Thornley | These opinions are mine. I
da...@thornley.net | do give them freely to those
http://www.thornley.net/~thornley/david/ | who run too slowly. O-