I'm in one of the merely free-ish states that doesn't allow the full tube, so hypothetically 5+1.
However, as said in the thread all shells aren't the same, & in my rig which is Hornady slugs in the tube, only 4 fit. 5 almost does, but not quite.
I get around this by ghost loading, so I have 4+1+1 when topped off.
I don't store it that way however, when I store it & leave the house I empty the chamber first.