I've heard anecdotal stories of people being arrested at Logan when
they change planes with disassembled, unloaded firearms in their
checked bags. May be urban legend.

I have transported firearms via airlines many times including through Logan.
The trick is to transport them in airline approved carrying cases and declare
them when you check in. If in doubt call ahead. Ammunition must be in its
original box and the firearm must be unloaded.

Next time you go through luggage pick up look for luggage with bright orange
tags.

Dan, U. S. Air Force, retired