From The Truth About Guns:

Federal law states that people can’t be sued for engaging in lawful trade of guns and ammo. Oh, if someone breaks the law or if the products are faulty, that’s different, but just for engaging in lawful trade? Nope.

Of course, that doesn’t stop lawsuits from happening. Usually, they’re thrown out, but an anti-gun court decision against Remington didn’t just hurt the company, it’s likely to hurt the entire gun industry as now the vultures are out and about. Since a judge ruled that the lawsuit against Remington could continue, they’re hoping other judges will follow suit.