How about an e-mail bombardment to these people asking them to provide their "compelling evidence?" Make sure you make it sound like it's from a terrified soccer mom.
They really, really want to get those .50 caliber rifles banned, but for you hunters and sports shooters who still think you're off the hook, keep in mind that "high-powered weapons" includes your deer rifles and match rifles. They also want to register everything. Not just handguns. EVERYTHING.
(You know, we pro-self-defense types could be a very, very effective group if we'd just lose the conscience and the desire for honesty.)