This is an unedited run through TVHM M3 Heck using only the Ripper and the Facepuncher.
Along with apply artifact and melee shield effects, the facepuncher when used with Double Barrel applies Ripper’s bonus gun damage effect as long as the main Zane is holding it in his hands.
Spawn the clone with Facepuncher and switch to Ripper to reap the bonus damage. While utilizing melee gimmicks, this is a gun damage build. The bonus damage applies only to Ripper and anything that gives more gun damage is better, in terms of damage.
The cool thing about using the Facepuncher with this build is customization of artifacts based on your build preference. Shield is irrelevant too, but terror anointments slot into this build nicely.
I was using Terror ammo + Terror on action skill end for shield/grenade. Ideally, you would use an anointed It’s Piss for an additional 20% damage and with damage on terror for even more.
I am not using Barrier for 25% multiplicative bonus damage because my Ripper only has an anointment for +50% cryo damage and the clone is essential. Ideally you would run Clone/Barrier (even unaugmented) and have +130% weapon damage on swap.