Are you saying a good RNG is only doing 60% of the damage that a COR would? Or that a good RNG is doing 60% more damage than a COR could? I'm pretty sure its the second one but wanted to double check
Not him, but I'd say the accurate numbers (judging from Arebati) are: RNG does 60% of the damage, COR does 40% of the damage. So they do (roughly) 50% more than a COR does.
This isn't entirely fair though, since the COR is giving buffs to the RNG, and the RNG isn't giving buffs to the COR. If you had a RNG without any COR buffs, it wouldn't do as much damage (as the RNG with the buffs). In isolation, with ONLY one job or the other, you'd end up closer to each other.
This also assumes RNG is using less-than-optimal weapon/WS (Annihilator) to keep themselves from pulling hate. If they're allowed to full-time use Pinaka or Earp, they'd do a hell of a lot more damage. Before being murdered by their target.