Unknown container for an Atomic Demolition Charge M50 (ADC)

[auf270]

Hi - more than 30 years ago, this rather primitiv container found its way into the depot in the Museum for historic military technics in Roethenbach/Pegnitz near Nuemberg. According to an inscription it was intended for the transport of an Atomic Demolition Charge M50. A manual of the Nationale Volksarmee (NVA in the former GDR) from 1978 defines the ADC M50 as an atomic mine with a diameter of 20 cm and a weight of 72 kilos.
It can be assumed, that the container was intended as fake for education purposes.
Any suggestions.

 

[auf270]

I forgot some more informations: the box containes a hollow cylinder made with two steel tubes with the space between filled with concrete. The inner tube has an inner diameter of 20 cm. The lid is missing.
The manual defines the ADC as charge of the cannon type. In 1978 it was obsolete in the US Army.
The ADC was made during the cold war for delaying an enemy's advance near the border by blowing up roads.