A federal grand jury has indicted 11 people for possession of machine guns or small devices to convert semiautomatic weapons to fully automatic, officials announced on Friday.Jonathan S. Ross, acting U.S. Attorney for the Middle District of Alabama, announced the arrests at a news conference. Officials said they hope the announcement and the prosecutions can deter what they said has been a growing threat to public safety and law enforcement. They said the small machine gun conversion devices, or Glock switches, are readily obtainable.“Our goal today is to get the word out that, one, these devices are illegal,” Ross said. “They’re illegal in and of themselves. Federal law considers the device itself to be a machine gun and possession of it is punishable by up to 10 years in prison. We want to get that word out. And these prosecutions, our hope is that they will have a deterrent effect.”Ashley Lightner of the Bureau of Alcohol, Tobacco, Firearms and Explosives (ATF) said Glock switches allow a semiautomatic handgun to fire 20 rounds in one second.