While the Squadron putty was drying I cut the nose of an ESCI FFAR pod:

and inserted the base into the inlet of the APU to give it some detail.

Here’s how the outcome looks before paint:

The amount of putty required and the sanding is obvious on the series of pictures above, but let me tell you – this is a great stress-relief technique.

I also created a new gun mount to replace the missing part, using brass barrels of a design closest to the original GSh-30. These are fixed into a block of laminated styrene. The white brackets are scrap styrene sheet.