I wish Mr. Tresmond well but don't believe the bill passed is an ex post facto law. As I understand it, the law would grandfather in ten round magazines already in a gun owner's possession but limit the owner from loading more than seven rounds in the magazine. A law violates the Ex Post Facto Clause only when it criminalizes past action. It is the future act of loading or possessing a magazine with more than ten rounds in it that is being criminalized.
The Second Amendment itself provides a better chance of success than an ex post facto claim.
Jim's Rules of Carry: 1. Any gun is better than no gun. 2. A gun that is reliable is better than a gun that is not. 3. A hole in the right place is better than a hole in the wrong place. 4. A bigger hole is a better hole.