You can buy gun magazines without a license if you are purchasing them from a firearms dealer or manufacturer. If you are purchasing them from an individual, you may need to obtain a background check and/or permit depending on your state’s laws. In some states, it is also legal to purchase gun magazines through the internet or by mail-order.
However, it is important to note that federal law prohibits the manufacture, sale, or transfer of high-capacity ammunition feeding devices (i.e., gun magazines that can hold more than 10 rounds of ammunition) regardless of whether or not a person has a license. Also, some states have enacted their laws banning high-capacity ammunition feeding devices even though federal law does not currently ban them. So, it is always best to check with your local laws before purchasing any type of gun magazine.