As I understand what coyotewacker is proposing, the actual threads are cut into the barrel and a "spacer" is heat shrunk to a straight turned section of the barrel behind the threads and provides a larger diameter shoulder for the suppressor to contact. No suppressor launchin unless the end of the barrel breaks.
OGB, I like your reasoning!
Can't cause the barrel is too small to thread. So proposing turning the end few inches of the barrel down even smaller, and straight, sliding a bushing sleeve over to increase the barrel diameter. The threading would be on the new sleeve. No mechanical connection between the sleeve and the barrel. That is what raised a red flag.
In theory it should work.
