In every instance cited, and the most sensational gun tragedies, new registration would not have helped. Guns are possessed by felons daily and not purchased from gun stores or from gun fairs. Young folks and convicted felons are already violating laws that have caused horrible tragedies and stole the guns from registered owners, or obtained already stolen property on the street. Making more laws is only going to affect the already over-regulated law-abiding public.
Want to help? Lobby heavily for mandatory detainment for the mentally ill. Fully fund the state mental institutions and make the minimum evaluation time seven days. Do not release people that are even marginally ill. Implement a parole board-type panel to review who gets out, how and when.