On April 4, 2013 Connecticut changed it's magazine restriction laws after the attack on Sandy Hook Elementary School. There is now a magazine limit of 10 rounds. Any magazine that can hold more than 10 rounds is considered to be a LCM (Large Capacity Magazine). Any magazines that can hold more than 10 rounds owned before the date above must be registered to the Dept. of Emergency Services and Public Protection, this must be done within one year of the law passing. These magazines may not be loaded with more than 10 rounds. If the magazine is in the owner's home or a legal shooting range It may be loaded with more than 10 rounds.
Some states have a limit on the number of rounds a magazine can hold. In these states purchasing, selling, or transferring a magazine of larger size than the law allows is a crime. In some cases magazines that were bought before the law was put in place must be registered with the police, in others they may only be loaded to the number of rounds legal in a state. The law may vary in some cities.