This young Canadian was a wee bit overenthusiastic. Still, the attention to detail is remarkable. Incidentally, the V3 was seemingly inspired by the Petlyakov TB-7 or Pe-8 heavy bomber, a type of aircraft presumably photographed for the first time in the West when used to fly Soviet Foreign Minister V.M. Molotov to the UK and back to the USSR in May-June 1942.
Apologies for the limited resolution of the image.
The main weapons appear to be 54 mm (semi?)automatic guns (nose, mid upper and belly twin mounts) and 32 mm (semi?)automatic guns (wing tips, mid upper and tail fins quadruple mounts). The pair of 12.7 mm machine guns in the nose seems out of place.