Pretty much what
@cryptic__egg said.
Another thing to look into is muzzle loaders and black powder firearms that is listed in the firearms megathread, as that one is oftenly overlooked for more conventional, modern firearms. It is usually used for props, cosplaying, and acting roles in drama (you could claim that you are doing an act or something for a hobby, or some alibi other than CTB'ing). If you do consider muzzle loaders, it may take a bit more steps to get acquainted or operate it, but it should be fairly reliable (I never used one so I'm not going to make any absolute claims on it) to CTB with. As always, do carefully study it and if you don't feel comfortable with it, you could choose another method. I hope this is helpful.
https://sanctioned-suicide.net/threads/guns-firearms-megathread.9042/