I’ve started from the concept of sci-fi turret by George Hull, but I decided to modify it. I was doing it without high poly, but I placed fine details like nuts and screws using Blender’s add-on “Decal machine”. For making UV I’ve used Maya. Also I’ve planned to use the bevel shader for getting the beveled edges on a normal map after baking and Blender made it perfect. Then I’ve textured it with Substance Painter. Final render on previews I’ve made with Blender’s Cycles.

After that I've decided to make a rig and animation, and then render it within UE4. After rigging and making few fire animations I made Animation Graph and Event Graph, and then Blueprint Event Graph. It allowed to call the fire animations and animate the movements directly from sequencer - pretty comfortable. I've also created the muzzle flashes through the particle system and synchronized them with sound effects through the animation montages. In the end I've found few interesting shots and rendered in 4K with UE4.

The UE4 project has materials, particle system and sound effects. Also the skeletal mesh has LODs:

LOD0: 216 506 Tris, Screen Size > 1.4;LOD1: 54 126 Tris, Screen Size > 0.65; LOD2: 27 063 Tris, Screen Size > 0.45; LOD3: 12 990 Tris, Screen Size < 0.45;