In a 1v1 situation, silence him with running blast and deal damage until he uses emitter, then channel recharge towards him until he runs out of shields then finish him. Nimble would be perfect to keep pressure on him if he tries to run away.
use cover to get close and then use runic blast, shield recharge(if his shields are up), lock on attack(until he starts shield melting you). then move to other targets and into cover
Using your Runic Burst to force reload is great for stopping Ruckus from spamming bullets. Watch your shields though, especially if the Ruckus is carrying Wrecker.