Pro-firearms industry members of Congress have used both the law and intimidation to limit & restrict federal money from being used for research into gun violence (if the results of the research could be used to justify gun control).
The amount of money in question is not very large. When Rep. Jay Dickey (R-Arkansas) first pushed the issue, it was $2.6 million. See HowCongress Blocked Research on Gun Violence (Slate, Paul D. Thacker).
Here’s how Illinois (or any other state) could pressure Congress to reverse this decision.
Illinois could fund firearms research in Illinois with revenue generated by an annual registration fee on firearms. A fee of $20/firearm (exempting the first three firearms) plus a tax of one penny on every bullet sold in Illinois, would provide plenty of revenue for research on gun violence.
The law would be structured to take effect one year (or so) after passage, if Congress has not fully funded research into gun violence, including research by the Center for Disease Control.
To define “fully funded” it should be the same percent of the CDC budget as before Congressional meddling or whatever level the CDC recommends, whichever is higher.