Try as he might I think Obama is going to have enormous trouble getting the Americans change their mind set about gun control. Even in the wake of this latest shooting. It's in their Constitution the 'right to bear arms' clause, without thinking when this bill was drawn up to help the Americans fight their cause in the Revolution.
Unless you are a hunter, I can't think of any reason to own masses of guns. Most of the guns owned by the common man are for killing people not animals, some are really powerful - the type used by an army. So why do they need them in their own home?
After they have finished mourning for these poor little children and their teachers, they will carry on using and buying guns.