It is not illegal to tell/show how to do it. It is illegal to do it. There are many videos and instructions, on the internet, showing how to do it, and how they operate. I've seen exact instructions and dimensions as to how to make an auto sear.

The laws are so tough that it is against the law to have possession of an unregistered auto sear, and also a gun capable of using that auto sear. It doesn't have to be installed, just having it and a gun that can use it, could put you in jail for 10 years. The Feds.

Bob