Md. Code, Criminal Law § 4–305

(a) This section does not apply to:

(1) a .22 caliber rifle with a tubular magazine; or

(2) a law enforcement officer or a person who retired in good standing from service with a law enforcement agency of the United States, the State, or any law enforcement agency in the State.

(b) A person may not manufacture, sell, offer for sale, purchase, receive, or transfer a detachable magazine that has a capacity of more than 10 rounds of ammunition for a firearm.