I support common sense gun laws but this issue can't be the Dems top priority. Gun control and gay marriage are just not issues where national majorities are made. It's about breaking the GOP's interest groups stranglehold on politics and I would start with their business interests long before taking on the NRA.
The problem for the Democrats is that not all of the gun laws progressives support are common sense. Indeed, some of them are just plain nonsense, and supporting them weakens support for the ones that truly are needed such as universal background checks.