The reason they are called petty criminals is because they commit petty crimes which would not include the use of guns. If they use guns in a crime the crime is no longer petty and becomes a major crime. Petty criminals is not the problem but major criminals are. A normal law abiding person has no idea if it would be easy for a criminal to obtain a firearm or not. An experienced police officer, like I was, would though. The ease of obtaining firearms anywhere in the world is made easier by the amount of money the criminal is willing to spend and the contacts he has in the criminal arena.