K-Rom, MD has state preemption of all firearms laws. Not to say that MoCo wouldn't charge someone anyway, but it's good to know nonetheless.
That preemption statement is true "generally," but the preemption statute gives localities control over the "safety zone" and as regards to "minors." Everyone here should be aware of how that raises the potential for bad stuff . . .
http://michie.lexisnexis.com/maryland/lpext.dll?f=templates&fn=main-h.htm&cp=
§ 4-209. Regulation of weapons and ammunition.
(a) State preemption.- Except as otherwise provided in this section, the State preempts the right of a county, municipal corporation, or special taxing district to regulate the purchase, sale, taxation, transfer, manufacture, repair, ownership, possession, and transportation of:
(1) a handgun, rifle, or shotgun; and
(2) ammunition for and components of a handgun, rifle, or shotgun.
(b) Exceptions.-
(1) A county, municipal corporation, or special taxing district may regulate the purchase, sale, transfer, ownership, possession, and transportation of the items listed in subsection (a) of this section:
(i) with respect to minors;
(ii) with respect to law enforcement officials of the subdivision; and
(iii) except as provided in paragraph (2) of this subsection, within 100 yards of or in a park, church, school, public building, and other place of public assembly.
(2) A county, municipal corporation, or special taxing district may not prohibit the teaching of or training in firearms safety, or other educational or sporting use of the items listed in subsection (a) of this section.
(c) Preexisting local laws.- To the extent that a local law does not create an inconsistency with this section or expand existing regulatory control, a county, municipal corporation, or special taxing district may exercise its existing authority to amend any local law that existed on or before December 31, 1984.
(d) Discharge of firearms.-
(1) Except as provided in paragraph (2) of this subsection, in accordance with law, a county, municipal corporation, or special taxing district may regulate the discharge of handguns, rifles, and shotguns.
(2) A county, municipal corporation, or special taxing district may not prohibit the discharge of firearms at established ranges.