In the entire U.S. there are an estimated 20,000 or more gun laws.
Like most states, there are far too many gun laws for a brief answer here on Answers.com. However, this is a link to a review of several of their gun laws. https://en.wikipedia.org/wiki/Gun_laws_in_Louisiana
There are thousands of laws that relate to gun control, and cover every state. Those laws have been there for years.
Your question calls for an opinion. My opinion is that most gun laws are useless. There are several thousand gun laws on the books NOW in the US. Many of them make little or no sense.
The first layer is federal gun laws. From there State laws can restrict gun laws more, but not make them more liberal. From there County laws/ordinances can restrict more so, but not make them more liberal. <><><> Above is correct, but with an exception- Many states have enacted "preemption" statutes, to prevent a "patchwork quilt" of gun laws that vary dramatically city to city, county to county. In those states, the State Legislature preempts the ability of a county to pass gun laws, reserving that right to itself.
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No matter WHERE you use a gun, there are laws that govern what you can and cannot do. If you do not know those laws, please do not own a gun.
Your question is an incorrect statement. Why do you think states must not enforce gun laws? They do.
That is too broad of a question to answer as asked. Is there some specific information you want about gun laws?
Depends on the laws where YOU are (we get questions from many different countries). In MOST of the US, no.
Literally, tens if not hundreds of thousands of laws. My copy of US state gun laws is about 2 inches thick. It is estimated that there are more than 20,000 gun laws in the US- and you are asking about "around the world".
barak obama is pushing for more vigurous gun control laws and background checks
It is a meaningless term that sounds good. A dealer, selling firearms at a gun show is subject to the same laws, procedures and recordkeeping he is subject to in his shop. At many shows, a private citizen that has a gun or two they want to sell can do so, subject to the same laws and procedures if they sold their gun at home.