Just because you have a card, doesnt mean you use.
Its a states rights issue, schedule one, and 4473 are both federal.
But far more importantly is the law itself which states : (snip)
MICHIGAN MEDICAL MARIHUANA ACT (EXCERPT)
Initiated Law 1 of 2008
Sec. 4. (a) A qualifying patient who has been issued and possesses a registry identification card shall not be subject to arrest, prosecution, or penalty in any manner,
or denied any right or privilege, blah blah blah
provided that the qualifying patient possesses an amount of marihuana that does not exceed 2.5 ounces of usable marihuana,blah blah blah,
in other words, you are protected by statutory law from being forced to relinquish any constitutional rights because you have this card, or the legal amounts of this medication.
including guns