It is not quite that simple. Even with a class III dealers licence any post 86 machine gun is considered LE only or a dealers sample. You will still have to show documentation that you have arrangements to demo said weapon to a LE agency for potential sale. Even then you must maintain the license forever or lose the weapon.
In life, strive to take the high road....It offers a better field of fire.
"Robo is right" Fuzzball