PA Luty ... a Brit so incensed by his own government when they stripped Britons of their guns that he published and distributed the 'Expedient Homemade Firearms Manual'. (available on Amazon and other online sources)
Expedient Homemade Firearms: The 9mm Submachine Gun: P.A. Luty: 9780873649834: Amazon.com: Books
The manual contained plans, templates, and instructions for the manufacture of fully automatic firearms with common shop tools and easily obtainable materials.
Mr Luty was arrested five times in ten years for lengthy periods but never convicted of a single crime. Mr. Luty passed from cancer in 2011 but his plans and designs are more available now than ever and have been made in the tens of thousands.
Firearms are great provided the law backs you up on when using them. If you use firearms illegally, you are no better than the criminal as far as the law is concerned.
I live in Ohio and have my CCW. Our laws support the legal carrier in the event of needed deadly force. However even if my license were acceptable in places like New York or California, I would be scared to use deadly force because those states look down on citizens defending themselves.
From a legal standpoint, guns are only as good as the laws that support your use of them. If the laws do not support using your firearm, you can land up in prison just like a criminal robbing a convenience store.