As of right now, open fire provides no further bonuses after rank 5. Rank 5 lasts 12 seconds, and anything past is still only 12 seconds. This was the same in potco. Is this intentional or does it need to be fixed?
I'm not sure if it was intentional. I just chucked 3 points into mine and let the rigging do the rest. Perhaps they thought any duration more than 12 seconds would be overpowered. It doesn't bother me much though. That's just 2 extra points I get to spend somewhere else for more utility without worrying about missing out.