The subcaliber shells made from chrome-vanadium steel were able to penetrate much more than 4 metres (13 ft) of reinforced concrete roof before burying the shell through the floor and into earth.[2] They resembled fin-stabilized arrow shells, but had a discarding flange acting as a driving band instead of fins.[3] Despite high penetration, these shells had a low muzzle velocity, and thus a high dispersion, 36 m (118 ft) on 1,000 m (3,300 ft) range. As a result, they saw very limited use during World War II; only about 200 shells were ever fired even though 6,000 such shells were made for the very large howitzers like the 21 cm mortar.[citation needed]
Impact of a Röchling shell that hit Fort d'Aubin-Neufchâteau. Picture is taken around 20m underground.
Röchling shells were tested in 1942 and 1943 first against the Belgian Fort de Battice then against the Belgian Fort d'Aubin-Neufchâteau.[5][6] They were also tested against the fortresses of Hůrka,[7] Hanička and Dobrošov[8][9] (today's Czech Republic),[10] the Gössler wall, Toplitzsee (Austria) and at the Hillersleben test facility (Germany).
They were regarded as a German secret weapon, and there is speculation that their use was limited in order to reduce the chance of dud shells being recovered and exploited by the Allied forces.[11] A more likely reason, however, is their poor accuracy.[12]
Preserved small-size fin-stabilized prototype of Röchling shell (36 cm long) is since 2020 exhibited in the Museum of Czechoslovakian fortifications,[13] inside the fort Hůrka [cs]. Remnants of full-sized test shells are still visible in the walls of the fort.[14]
^Basil T. Fedoroff; Henry A. Aaronson; Earl F. Reese; George D. Clift (July 7, 1958). "Röchling Anticoncrete Projectile". Dictionary of explosives, ammunition and weapons (German section). Picatinny Arsenal. p. Ger 160. doi:10.21236/ad0160636.
