They played you! Asking how something is done or could be done is a common tactic used by lawyers, reporters and law enforcement - to find out if you really do know what you're talking about and also to give you a case of diarrhea of the mouth while trying to impress them. Also, my "educated" guess is that you were also recorded and didn't know it. Later, the recording would have been run through a VSA. There are a couple of other "tricks of the trade" they probably used on you as well. They're trained to do that, and most of them are pretty good. And, you mentioned there were two agents. Care to guess why that was?<quoted text>
I don't make threats. The GBI agent asked a question that lead to him asking me how to make one. Things I was taught were not to be discussed with civilians. The boom part isn't hard it's making it go boom that is, was my answer.
Finally, your military "record" is NOT on your Facebook page, just a reference to a 81-82 stint with Special Forces.