A bump fire stock that attaches to an semi-automatic assault rifle to increase the firing rate is seen at Good Guys Gun Shop in Orem, Utah, U.S., October 4, 2017.

The Supreme Court on Monday rejected a new effort to expand gun rights by declining to hear a challenge to a Trump-era ban on so-called bump stocks, which allow semi-automatic rifles to fire more quickly.

The decision not to hear the two related cases, a blow for gun rights activists, leaves the ban in place. The conservative-majority court issued a major ruling in June that expanded gun rights, although the legal issues in the bump stock cases were different.