Owning a gun that is not licensed are illegal. Buying an unlicensed gun is also illegal. To make a gun however, is a different ball game. If you have the technical skills to design and construct a gun will never be illegal. You cannot determine a particular skill or knowledge to be illegal that would be taking away a person’s right to think. The way you use your technical skills and knowledge and the results of your application can be illegal though. Buying unlicensed guns are illegal but if you are able to make a weapon it is not however, owning an unlicensed gun is illegal.