In the meantime I started to paint the pak. I started with primin using Gunze Resin Primer, and then coating the gun with a layer of Tamiya German Grey. This was followed by some subtle sponge chipping, showing red primer marks. These spots were then occasionally painted with a black brown color simulating bare metal.

Then I added a filer using a beige brown oil mixture, followed by a black brown pin wash. To ease painting, I still keep the upper part of the gun separate from the base:

For the pictures, the gun was put together on the base.

Update: Now the gun is finished, and I fixed it to the base. Currently I am still working on the grenade cases. Then the gun crew will be sculpted…