Experts have identified restrictions on high-capacity magazines as a factor that could make mass shooting attacks less deadly. Between 1994 and 2004, the Federal Assault Weapons Ban prohibited new magazines over 10 rounds in the United States. After the expiration of the ban, there is no nationwide prohibition against the possession of drum magazines, which are considered an regulated firearm accessory. However, as of 2019, ten states set a maximum limit on the capacity of magazines, including California, New York, and Colorado, plus the District of Columbia.