New turret - needs better textures.

I think I've finished the major modelling, leaving probably only little tweaks. Now I need to do materials and textures, which are really not my strong-suit.
I've tried to add a little wear to the parts of the barrel that will slide back with recoil, but it doesn't quite work, yet.
I'm not too sure about the sensor turret at the back. I may rebuild much of it, or even go for a completely different sort of thing, if I decide I don't like it.
I look forward to hearing what anyone thinks of any aspect of this, and would love to answer any questions, particularly technical.