You are quite amusing. The ATF does not consider cannons built before 1898 and their replicas as destructive devices - not regulated by the ATF. Those types of cannons were used on the battlefield and on the water for hundreds of years. I don’t believe even you would not consider them destructive. However, a breach-loading cannon of any size is considered a destructive device and is regulated by the ATF.
Muzzleloading cannons manufactured in or before 1898 (and replicas thereof) that are not capable of firing fixed ammunition are considered antiques and not subject to the provisions of either the Gun Control Act (GCA) Gun Control Act | Bureau of Alcohol, Tobacco, Firearms and Explosives or National Firearms Act (NFA) National Firearms Act | Bureau of Alcohol, Tobacco, Firearms and Explosives. [26 U.S.C. 5845; 27 CFR 479.11] Last Reviewed April 20, 2020"
Are muzzleloading cannons considered destructive devices? | Bureau of Alcohol, Tobacco, Firearms and Explosives
You are welcome to believe what you may. The reality is quite different. One aspect to consider is as the laws make firearm ownership more onerous, expensive, and legally perilous, it does discourage and prevent people from owning firearms. Firearm ownership rates between restrictive states and more liberal states are proof of that. If a law prevents one from owning a firearm because you can no longer own it, or the fear of breaking a Byzantine law, it is the same as an out-right ban. Our country is founded on a principle of egalitarianism. If laws prevent some people from exercising their rights, it is unjust. “Gun control” laws do exactly that. Firearm ownership by minorities and women in restrictive states is far lower than in more liberal states. Most firearms are owned by wealthy, old white men. Apparently you are fine with that.
Why does our government need to know what firearms we own? If you are not committing a crime, what difference does it make? Many want Marijuana legalized, but it was made illegal purportedly to protect the public. “Gun control” is promulgated under the same ruse.