That's good. In Arizona we already have a law like that:

12-714. Actions against firearm manufacturers; prohibition; findings; definitions

A. A political subdivision of this state shall not commence a qualified civil liability action in any Arizona court.

B. The legislature finds that:

1. The citizens of this state have the right, under the second amendment to the United States constitution and article 2, section 26 of the Arizona Constitution, to keep and bear arms.

[b]2. Lawsuits have been commenced against the manufacturers, distributors, dealers and importers of nondefective firearms for the harm caused by the misuse of firearms by third parties, including criminals.

3. Businesses in the United States that are engaged in the lawful sale to the public of firearms or ammunition are not, and should not be liable for the harm caused by those who unlawfully misuse firearms or ammunition.

4. The possibility of imposing liability on an entire industry for harm that is the sole responsibility of others is an abuse of the legal system, threatens the diminution of a basic constitutional right and constitutes an unreasonable burden on the free enterprise system.[/b]

5. The liability actions commenced by political subdivisions are based on theories without foundation in the common law and American jurisprudence. Such an expansion of liability would constitute a deprivation of the rights, privileges and immunities guaranteed to citizens of this state under both the Constitution of Arizona and the United States Constitution.

... Yeah. You go miss Arizona!