I'd bet it is a hoax. Some bulgarian smartass manufacturing these from old factory rollers/drums and making a good profit of it .
Don't think so, don't know though. Proper chap selling it, & they appeared to have all the bits of a real case. We assumed cut & cleaned/painted one like these: http://www.wheatcroftcollection.com/dora.html Lord knows though. It'd make a nice planter, or patio fishpond. Or micro-shed. http://www.scribd.com/doc/153115946/Dora-Projectiles
27-9-13 Friday 20.00 Another Monster Move extravaganza featuring dire consequences of collapse and exterminating all known life. This time the move of a WW1 Rail Mounted Gun from Hampshire / Wilts to Utrecht in Holland.
I don't think this article has been posted here before. Krupp 80 cm Kanone Schwerer Gustav (Dora) Railway Gun