§ 5-133. Restrictions on possession of regulated firearms.

(d) Possession by person under age of 21 years prohibited; exceptions.-
(1) Except as provided in paragraph (2) of this subsection, a person who is under the age of 21 years may not possess a regulated firearm or ammunition solely designed for a regulated firearm.

(2) Unless a person is otherwise prohibited from possessing a regulated firearm, this subsection does not apply to:

(i) the temporary transfer or possession of a regulated firearm or ammunition solely designed for a regulated firearm if the person is:

1. under the supervision of another who is at least 21 years old and who is not prohibited by State or federal law from possessing a firearm; and

2. acting with the permission of the parent or legal guardian of the transferee or person in possession;
(ii) the transfer by inheritance of title, and not of possession, of a regulated firearm;
(iii) a member of the armed forces of the United States or the National Guard while performing official duties;
(iv) the temporary transfer or possession of a regulated firearm or ammunition solely designed for a regulated firearm if the person is:

1. participating in marksmanship training of a recognized organization; and

2. under the supervision of a qualified instructor;

(v) a person who is required to possess a regulated firearm for employment and who holds a permit under Subtitle 3 of this title; or

(vi) the possession of a firearm or ammunition for self-defense or the defense of others against a trespasser into the residence of the person in possession or into a residence in which the person in possession is an invited guest.

Quote:
§ 5-134. Restrictions on sale, rental, or transfer of regulated firearms.
(b) Sale, rental, or transfer of regulated firearm prohibited.- A dealer or other person may not sell, rent, or transfer a regulated firearm to a purchaser, lessee, or transferee who the dealer or other person knows or has reasonable cause to believe:

(1) is under the age of 21 years;
...
(d) Sale, rental, or transfer of regulated firearm to minor prohibited.-

(1) A person may not sell, rent, or transfer:

(i) ammunition solely designed for a regulated firearm to a person who is under the age of 21 years; or

(ii) 1. a firearm other than a regulated firearm to a minor;