MauiWowie
I have the SIGness...
Under either bill, if you lawfully owned the firearm on October 1, 2013, you can take it to the range and shoot it. If a person acquires a new banned weapon after October 1, 2013 (unless previously ordered), he commits a criminal offense, unless he falls into the narrow exception clauses.
In prosecution for such an offense, the state would have to prove beyond a reasonable doubt that it was acquired after the effective date of the ban, if I am not mistaken. If I owned such a firearm, I would take the reasonable precaution of documenting that I lawfully possessed it before October 1, 2013. I am not a lawyer and this is not legal advice. It is just what I would do.
How would you do this? Pictures with newspaper?