What kind of weapon is it and where are you?
No
Do you have the title of the car in your name? Is there a loan on the car? You will have to register it if your name is on the title!
Yes you can register it but be prepared to pay a penalty.
No. You do not have to register any weapon in Missouri. The only permit needed in Missouri is the permit to carry a concealed weapon.
If they pass the requirements where they live and register the weapon.
to any dealer
No. Unless it is a fully automatic weapon (often referred to as an "NFA Weapon) There is no requirement to register firearms anywhere in the State of Florida.
Simply take the title and proof of insurance to you local DMV in your city, and they will register the vehicle.
You can register it but someone else has to drive it.
Yes, a weapon is a weapon.
Someone
Yes, the day you register it, you will pay taxes.