Well eventually all the private guns not subject to background checks will disappear by attrition. This won't happen overnight, but it is a step in the right direction. Bottom line is if someone uses an illegally obtained weapon in the commission of a crime he/she will sing like a canary when caught if there is even a hint of a reduced sentence.
I think the whole "assault weapon" issue, unfortunately, is too fuzzy to be enacted, but the background check is not.
As for the clips, I claim ignorance, however no one needs a clip of 30 rounds, let alone several of them.
Maybe there should be some kind of restriction on bullets.