The correct understanding of what you pointed out is that the states have the authority to regulate everything you noted not that they are "universal". Speed limits? set by states, drinking age...set by states(albeit strong armed by the Fed), smoking age...set by states. See the pattern there?
And the more important point which you have missed is that the federal government has limited authority when it comes to making "universal" laws. It is important to understand that, particularly when the proposed "universal" laws apply to a fundamental right to which the federal government is expressly constrained from restricting.
My point was not weather the federal government CAN make a law for all 50 states, just that if there was SOME continuity among ALL 50 states the average person would not have to waste their time to know if they can (fill in a state firearm law here) across a state line that might be 5 minutes from there house.
I spent more than a year reading here before I purchased my first firearm, so I think I am a little more educated than John Q Public.
The first time my wife and I traveled out of state she was adamant we not have a gun in the car because she thought it was illegal.
Ask your non-gun owning friends, family or co-workers about interstate gun laws, and see what they "know". Then ask about the drinking age, or what a speed limit sign means from state to state, or even buying a car from a different state (
One of the reasons people jump on the "gun control" bandwagon is because they are uninformed. One or the reasons they are uniformed is because there is little or no continuity in laws from state to state.
In this specific case, please cite the authority with which the federal government can regulate an intrastate transaction between two private persons.
I was not saying they could. My only thought was I should not need to spend hours to learn another states laws to sell a gun. If they were at least SIMILAR, like the drinking age per se, The chances of unknowingly breaking a STATE law would be a whole lot less.