So what does uncased mean? Does my laptop bad from the original post count as "cased"?
IANAL, but I believe this would satisfy the "enclosed in a case" requirement. The problem with this scenario as I see it is the prohibition on carrying
a rifle or shotgun with ".....cartridges or shells in.....the magazine.....thereof."
M.G.L. c.269 s.12d states:
(a) Except as exempted or provided by law, no person shall carry on his person on any public way a loaded rifle or shotgun having cartridges or shells in either the magazine or chamber thereof. For purposes of this section, “loaded shotgun or loaded rifle” shall mean any shotgun or rifle having ammunition in either the magazine or chamber thereof, such ammunition including a live cartridge, primer (igniter), bullet or propellant powder designed for use in any firearm, rifle or shotgun.....
This seems to say that you wouldn't be able to possess a loaded magazine while in possession of said rifle or shotgun, or it would be considered "loaded".