Well that would limit it to squeeze bore guns, the only weapon that comes close to the size of that barrel in the Pzkpfw IV would be the Pak 41 75/55mm (Unless they experimented with a different 75mm weapon as it is too big for the 42/28mm barrel) View attachment 14825 The barrel of this weapon though is not a uniform taper as it is made in three pieces, parallel barrel then the taper then parallel again, this leaves it with a distinctive band around the centre of the barrel (similar to the modern bore evacuators). View attachment 14828 I have not seen any reference to it being trialled in a tank though.
Nice one I have never seen or heard of those prototypes before, I am now having nightmares about Pzkpfw IV's (and Tiger Bergpanzers but thats another story). So here is something completely different. View attachment 14831
I know this is odd but any guesses, it was designed for one purpose but was found to be very good for other uses.
They do look a bit like Russians, but the guy in front appears to be holding a Thompson and of course it's a Bren in back. Got some tracks on it! Maybe a Weasel, whatever the official nomenclature was?
The track to width ratio is amazing, looks like it was designed for snow operations. The troops look like commandos.
I agree with you Tos as these are double tracks for the snow and boggy conditions, But I can't indentify the tracks, Perhaps something on the lines of a modified T40 or T70, Just thinking
dazzerjeep that would give it away. It was one of the biggest producers of war material during WW2 though.