Heller allowed reasonable restrictions, so you don't have a strong realistic argument about infringement. Note, Heller and McDonald did NOT wipe out gun laws.
To monitor ammo sales, amounts of guns - would take an incredible data processing entrerprise and cost a fortune. Look at the Canadian Registry fiasco. The country is in no mood to do such.
Politico.com had a good analysis of gun legislation. Their take is no chance of draconian measures. The pockets of urban antigun culture in NY, MA, CA or IL will speak up. Say Bloomberg, mayor of big cities even in gun states that face lots of urban crime. The victims or witnesses to gun violence like Feinstein or McCarthy will again speak up. But the chances of new bans are incredibly small. The current administration with a very tight election won't go officially near it.
Yes, the UN and a re-elected President will take immediate control of the country and giant robots will come for you. Realistically, we've been through Columbine, VT and Giffords with the same news stories, experts and nothing happened. Gun sales increase, many states improve their gun laws.
I'm not particularly scared of bans, etc. Fun to fret on the Internet.
We have reasonable takes on mental illness on the 4473. In fact, Cho was not reported as he should be. Idiots give guns to mental ill kids like Kip Kingle. Parents don't monitor their kids like the Columbine shooters.
So without absolute bans and confiscation (which won't happen), there isn't more to be done. Gun control advocates don't think through their suggestions, and pro-gun folks can get all in a tizzy. The AWB fight and subsequent elections and SCOTUS decisions made politicians outside of the anti-enclaves very leery of such pop ranting.