Black base. Instead of Grey primer.

 This looks an interesting painting technique.  Think I will try this out on my next model.  One has to experiment sometimes.   Check out the video.   The video is from Doog's video channel on you tube.

AvHistroy blog

Found this blog AvHistory.   The blog has some great information in the blog.   Here is a link:

Avhistory

Take a look you might be surprised.