Gauss Pistol. I used hard edge subdivision modeling, ZBrush, and Substance painter to create this asset. There were multiple barrels and magazines created for configuration options.
Gauss Piston barrel 1 with drum magazine
Gauss Piston barrel 2
Gauss Piston barrel 3
Substance Bake test 01
Substance bake test 02
Substance bake test 03