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From: thos@softway.sw.oz.au (Thomas Cohen)
Newsgroups: sci.military
Subject: Re: Pouring concrete (as regards Iraqi shelters)
Summary: Full chapter and verse
Message-ID: <1991Feb21.031753.12785@cbnews.att.com>
Date: 21 Feb 91 03:17:53 GMT
References: <1991Feb15.065035.8570@cbnews.att.com> <1991Feb18.054239.11447@cbnews.att.com> <1991Feb19.032729.18565@cbnews.att.com>
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From: thos@softway.sw.oz.au (Thomas Cohen)
In article <1991Feb18.054239.11447@cbnews.att.com> yarvin-norman@CS.YALE.EDU (Norman Yarvin) writes:
>
>A figure was mentioned of a German shell which penetrated 36m of Maginot Line
>concrete.
>
>Does anybody know whether this rumor was true?
>

Ain't no rumour. Following taken without permission from
(you guessed it) "The Illustrated Encyclopedia of Ammunition", by 
Ian Hogg. Spelling errors etc. are mine.

Rochling Shell  

  "Special type of anti-concrete shell developed by the Rochling Eisenund
und Stahl-werke of Dusseldorf, Germany during WW2.
  Conventional anti concrete shells of the period were full calibre shells
with blunt points; the Rochling designers reasoned that better penetration
would be achieved by a shell of small calibre, but delivering a heavier
blow by virtue of being much longer than normal and thus concentrating
its weight into a smaller area of contact. They accordingly designed a
long sub-calibre shell with a discarding sabot at the shoulder and a sabot
at the rear which enclosed a set of four flexible fins. When fired, the
shell left the muzzle and discarded the two sabots, allowing the fins to
spring out and stabilize it. It was fired from a 21cm rifled gun, but the
fins soon damped out the spin.
  The Rochling shell was not used against the Maginot line during the
1940 invasion of France, since it was not necessary. After the occupation
of France and Belgium a number of trials were made against fortifications
and one record of these tests reports of a shell which passed through 3m
of earth [ sorry, in the original posting I said 5m ], 36m of concrete, a
layer of broken stone, the roof of a subterranean chamber then into the
floor beneath and 5m into the earth beneath the floor. This was a test of
an inert shell; a live shell would have detonated in the subterranean
chamber if correctly fused.
  Achievement of this kind of performance demanded high grade chrome-
vanadium steel for the shell and precise manufacture. 8000 shells were
made and stockpiled, but after that it was hardly used. A few were fired
against the fortress of Brest-Litovsk during the invasion of Russia in 
1941, but use of the Rochling shell was then forbidden by Hitler on the
grounds that a specimen might fall into enemy hands and be copied for 
use against Germany. From then on the shells could only be used with his
permission, and since this was rarely requested and even more rarely 
granted, the existence of the shell was gradually forgotten."

-- 
thos cohen  				       |Softway Pty Ltd
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