Too many guns already exist and are on the market for even practical gun measures enacted right now to make a difference. Without ammunition to fire these weapons are useless.
Clever redesign and restriction of retail ammunition can answer most of the issues we grapple with today in the wake of the Newtown - and other catastrophes. Allow for the practical use of guns for hunting and recreation - with restriction in ammunition sold in certain calibers and types. Control and limit the weaponization of America - by driving up the operating cost of gun ownership. New technology can provide limited shelf life.
Guns don't kill people - bullets kill people.