Also, my point still stands - you first make bullets, then move onto weapons. To produce weapons, you need permission and a lot of red tape to cut through. Once you have that done, then you move onto grenades with even more tape. Then when you move onto grenade launchers, etc etc, you already have a wealth of knowledge on how to file every form, what you need to be able to produce it, about safeties.

The answer to your direct question is “I don’t know because I don’t make artillery”. The answer to “how do I make a medical device and have it be legal”, about which I know plenty, cannot fit into any number of comments. It’s something you do for a number of months, maybe even years. It depends on every country. It depends on the medical device. It depends on the people you have, on the money available. It isn’t an answer to a question.