Now that everyone has given their opinions, a few facts:
Federal law requires that a shotgun has a barrel at least 18 inches long, with an overall length of at least 26 inches
OR it must be registered with the Federal government and a tax paid.
All of y'all that said,"It ain't legal" are wrong. It CAN be illegal, but it can also be legal. Just like having morphine. It can be legal, but it can be illegal. Depends on how you got it.
See the gun? 11 inch barrels. Perfectly legal. Why? I papered it.
Now, I suspect, from the way the question was phrased, that the gun in question is not papered. If so, then it is illegal. Not because it is short, but because it is NOT PAPERED.
The state he lives in (don't know where Bizy is) might not allow it, even if it
is registered with the Feds. California don't. Neither does New York or Illinois. Probably others.