Unless I'm mistaken Riff's favorite personal weapon has been in the comic from early on. It has also gone through many iterations, the most recent being inflatable. In the DOR we've seen him putz around with various AIs (its been spec`d as a way replacing Kiki) Nano Tech seems to be the highest form of tech there, yet I don't think Riff has even bothered.
When we go back to the DOR do we see him making that cannon again for his plans with AI, or with nanos?