Gross Panzerfaust Hecht 10.5, 1/6

Early 1945 rumors, mostly from prisoner interrogations, had it that the russians were about to introduce a new heavily armored superheavy tank, called the "Schtschuka" (russian; "Pike"), into service at the eastern front soon. Immediately work on a corresponding anti-tank weapon began.
The submission from the company HASAG envisioned a so-called Grosse Panzerfaust ("Large Tank-Fist") based on the tube of the Panzerfaust 250 and a warhead capable of penetrating 400mm (15.75 in.) of steel.
Dynamit Nobel, another company, suggested the Hecht 10,5cm ("Pike", obviously because of its intended target) , a combination of the old Pionierhohlladung H 15 ("Engineer Shape Charge"), of which over 6000 were still in the armories, with the rocket propellant stage of the old RZ 65, an aircraft smoke rocket the Luftwaffe had never used in action. Diameter of the warhead would have been 26.5 cm (10.43 in.), the projectile itself would have been almost 90cm (35.43 in.) long. The firing tube had a caliber of 10.5cm (4.13 in.). Besides the fact that rarely any of the RZ 65s were left (most had been scrapped), trials showed that at least two propellants would have been necessary to shoot the warhead, which weighed over 15 kg (33 lb), to a distance of 100m (330 ft.).
Finally it was agreed upon a projected compromise of a new 7kg (15.4 pounds) shaped charge that was to have a range of 100m (330 ft.). Both the russian tank with the reported armor of 300 - 400mm (11.8 - 15.75 inch) and the AT weapon intended to counter it never materialized.