User blog comment:Argorrath/Ghosts Dynamic Bonus Map - Free Fall revealed/@comment-69.211.62.35-20130708202134/@comment-3967954-20130712214428

You've misheard. There's not a "thing" that prevents them from using futuristic weapons, but there is an apocalyptic event which means that the U.S.' firearms industry can no longer produce. Basically, they're stuck to using pre-event weapons.