A speed model turret I did for a class a few months back.
I was mostly focusing on clean topology, and need to definitely work on lower polygon count for my next speed modelling. This one ended up being just over 100k polys, with the bullets each being quite dense, so I should try and model quick, but keep good topology and poly count.
Ah well, was a learning experience!
Modelled in 3.5 hours using a Starcraft Turret as reference for the base.