Any barrier to getting new gun control measures passed will come down to how much the GOPers in the Senate are still beholden to the NRA and/or how much they still see a political benefit to towing the NRA’s line notwithstanding that group’s current meltdown. I don’t think many Senators are that ideologically committed to gun issues. It’s just that for years they have viewed gun rights absolutism as a key way to get support of their gun-nut base so that they can pursue the goals they really care about: slashing taxes for the rich and eliminating health, safety, labor, and environmental rules that hurt wealthy interests’ bottom line. Sure there might be a few GOP senators who are true believers in gun nuttery, but I really think they are the minority. The key to understanding the current Republican Party is they really only care about one thing. All those cultural issues (which is what gun control is for them) are just a means to advance their economic program to benefit the few at the expense of everyone else.