Hmm... what way might this go? The feds might try to ignore the Commerce Clause bit and go straight to the part that makes it illegal for the federales to enforce U.S. law in Kansas. We are all familiar with the way a Dem/lib government, and the current SCOTUS, bend into contortions to get a Dem law passed and through a judicial review.
But if you read the legislation it's only illegal if the feds try to enforce a gun control law on a firearm made, sold, and owned in Kansas. The state claims that any other federal laws that violate the Second Amendment are null and void, but that and a couple of bucks will get you a cup of coffee. They aren't threatening to interfere with those.