A federal judge granted a preliminary injunction yesterday, blocking a law that would raise the firearm purchase age in Colorado from going into effect. 

The new law, raising the age for purchasing a firearm from 18 to 21, was supposed to become law Monday. 

The complaint was filed yesterday in federal court by Rocky Mountain Gun Owners and two Colorado residents.  The plaintiffs claim the law is unconstitutional. U.S. District Judge Philip Brimmer granted the injunction.

The injunction temporally halts the measure from becoming law while the lawsuit plays out.