Welcome to America. We have laws that make it very difficult to protect yourself. 3./4's of Kalifornia won't issue concealed weapons permits. If you are attacked, defend yourself, you can pretty much count on loosing the gun, and maybe your right to own, for 3 years. It's called probation, since you would be carrying the gun illegally, despite a justified self-defense shooting. Bears, most of the time, have more rights then we do, or, a federal law that says carrying a gun in a Federal park is illegal, much less using it to defend yourself, or love ones.
I said all that to point out that the minimum length for a shotgun is at least 16" IIRC, and, it maybe 18.
You roll your dice, and you take your chances. Each gets to pick the chips they bring to the table.
S