I don't think it's fair to force an American citizen to serve in order to protect their family. I'm in favor of some kind of background/certification process, but let's be honest... neither of those really stops bad guys from accessing the millions of guns on the street. Right?
I'd say you're better off with a mandatory, minimum sentence of 10-20 years for any kind of a gun crime. And when you tell me the prisons are too full now, I'll tell you there's a lot of empty land out there just waiting for good fertilizer.