Colorado state senator Greg Brophy talks with Jon Caldera about universal background checks. It's from before the passage of HB13-1229 in the senate and it was heavily amended since then, but it's still informative about why universal background checks are a bad idea. For reference, here's a .pdf of HB13-1229, the Colorado universal background check law.
While I'm at it, here's Colorado senator Owen Hill, speaking quite poetically against HB13-1224 (the magazine ban, which I wrote about here) on the senate floor.
And while I'm still at it, here's Senator Brophy again, this time on the floor of the Colorado senate, explaining why the magazine ban should not be passed and should not be obeyed if it does. He failed at the former, but I'm pretty sure he succeeded in the latter.