the study showed something like 80% of felons got their guns from friends or family members.
If you're thinking of the same study I am, it was more like 50%. Theft (which background checks won't affect) was another 40%. Straw purchases (ditto) made up the difference. Gun shows were something like 0.7%.
We're being asked to accept a burdensome, defective system that won't stop guns from getting into the wrong hands.