With all the other guns, it was legal. The problem is the Bushmaster Assault Weapon, you can only drive to the range and back.
He’s not being busted for taking guns to the airport, he’d be in trouble if he stopped at a library and got caught.
You would think, wouldn't you, that a gun enthusiast in CA would try to make himself aware of the laws? For his own protection?
When dealing with the gubmint (and I spent years) remember the first rule of war. Always. Live by it.