A couple of things. #1 they are not serious about "protecting the children" or the effort would have looked much different. Their attempt was to pass ANYTHING that would hurt, tax, or inconvenience conservatives and progressives that go against thier program and buy guns.
#2 - "Gun violence" as they like to call it, would not be affected AT ALL by what was proposed.
#3 - The only way to significantly reduce deaths where guns are involved is to WADE INTO the bubbling, drug-infested areas where there is no respect for human life, take the guns, take the drugs, and make them live like normal people. "Gun violence" would be reduced by half with only gross measures. With an effort, it could go much lower- 60-75%. But there are a lot of reasons they do not want to do that, nor even ADMIT there's a problem (can you say, "Chicago"?).
#4 - Obama will not quit. Prepare for any and all executive orders that can restrict anything to do with guns, ammo, mental health, etc. and NONE of it will curtail crazy criminals from their acts, but they WILL affect law abiding conservatives who dare not to bow to his majesty.