Why do you want the government to license any part of your weapon.
The only reason to register weapons is so that the government can take them away.
If you do not believe that look at the history Germany, Russia, Japan, china, Poland. They all have registered weapons and they marched into homes, removed the weapons and then later came back and slaughtered their people by the millions.
Our founding fathers knew how bad governments can become and gave us the right to protect our selves from our government.
I spent more than half of my adult life protecting your rights.
Don't give that right away. It is the one right that protects the rest of the rights.