Medium demolisher killbox using only gun turrets and red ammo. All the turrents to the sides are disabled by the constant combinator. Lure the demolisher in from the bottom, once it is in range of the four turrets in the middle, they will take over the "guidance" and ensure that is destroys the constant combinator. At this point, all turrets will be enabled and start firing on the demolisher at once.
This allowed me to kill several medium demolishers without uranium ammo, tanks, nukes, or other more advanced methods.
I had weapon shooting speed at 6 and physical projectile damange at 9 when I did this.