In most states and counties purchasing a gun in America through a licensed gun dealer is relatively easy but does involve a background check and filling out a form 4473 and there may also be a waiting period for the gun transaction to be completed and finalized. For a semi-automatic firearm purchase you will need a certificate from a firearms safety training course and a more extensive background check in which there will be a mandatory waiting period depending upon the state or possibly the county that you are purchasing the semi-automatic firearm from.
While some states have enacted laws that preclude private gun transactions that don't also go through a licensed dealer in which the transaction is recorded, most states do not. Consequently, people that are disqualified from owning a gun or that prefer to make their gun purchases anonymous can easily circumvent the law by purchasing their gun from either a Gun Show or through a private sale transaction and this is routinely done in America.
While there is a lot to be said that private transactions should be allowed without interference between individuals for most things, when it comes to firearm sales that are transacted between individuals it would be far wiser that these types of sales be monitored by and recorded by a licensed dealer within the state. In particular, it is both dangerous and disturbing that individuals that are unable to pass background checks to purchase a firearm have an easy and an accessible way to purchase a gun in which there is no paper trail, no liability, and no recording of the activity that has been accomplished.
Gun Shows should be re-constituted so that only licensed dealers may sell guns and that all buyers of said guns must pass the same background checks that they normally would have to pass in order to purchase a particular firearm. That is to say, that all private sales should be prohibited as matter of course in Gun Show events, unless further transacted with an authorized and licensed dealer of firearms at the show.
To many people, however, there will be a hue and cry that we all have the right to bear arms and that anything that interferes in our ability to purchase said gun are as a matter of course a bastardization of our 2nd Amendment. While I do have some sympathy to this viewpoint, the fact of the matter is that guns are lethal weapons and that it is not unreasonable to establish strict, fair, and exacting standards in regards to the purchase, distribution, and resale of firearms.
Many people do not want the government to know their business, to know what they do or don't have, because they may legitimately fear the government and its military/police powers turning upon them in times of intense crisis or chaos. While this viewpoint has its place and its validity, we should be far more concerned about guns being in the hands of clear lunatics, unsavory characters, and violent criminals. That is our clear and present danger.