is it legal to carry a rifle in the trunk of my car?

[Domineaux]

Many posts have already covered the exact portions of law covering "preemption" such as:

Not "unconstitutional" per se, but clearly unenforceable. In fact the ordinance should not exist.

LOCAL GOVERNMENT CODE

TITLE 7. REGULATION OF LAND USE, STRUCTURES, BUSINESSES, AND RELATED ACTIVITIES

SUBTITLE A. MUNICIPAL REGULATORY AUTHORITY

CHAPTER 229. MISCELLANEOUS REGULATORY AUTHORITY OF MUNICIPALITIES


Sec. 229.001. FIREARMS; EXPLOSIVES. (a) A municipality may not adopt regulations relating to the transfer, private ownership, keeping, transportation, licensing, or registration of firearms, ammunition, or firearm supplies.
(b) Subsection (a) does not affect the authority a municipality has under another law to:
(1) require residents or public employees to be armed for personal or national defense, law enforcement, or another lawful purpose;
(2) regulate the discharge of firearms within the limits of the municipality;
(3) regulate the use of property, the location of a business, or uses at a business under the municipality's fire code, zoning ordinance, or land-use regulations as long as the code, ordinance, or regulations are not used to circumvent the intent of Subsection (a) or Subdivision (5) of this subsection;
(4) regulate the use of firearms in the case of an insurrection, riot, or natural disaster if the municipality finds the regulations necessary to protect public health and safety;
(5) regulate the storage or transportation of explosives to protect public health and safety, except that 25 pounds or less of black powder for each private residence and 50 pounds or less of black powder for each retail dealer are not subject to regulation; or
(6) regulate the carrying of a firearm by a person other than a person licensed to carry a concealed handgun under Subchapter H, Chapter 411, Government Code, at a:
(A) public park;
(B) public meeting of a municipality, county, or other governmental body;
(C) political rally, parade, or official political meeting; or
(D) nonfirearms-related school, college, or professional athletic event.
(c) The exception provided by Subsection (b)(6) does not apply if the firearm is in or is carried to or from an area designated for use in a lawful hunting, fishing, or other sporting event and the firearm is of the type commonly used in the activity.
(d) The exception provided by Subsection (b)(4) does not authorize the seizure or confiscation of any firearm or ammunition from an individual who is lawfully carrying or possessing the firearm or ammunition.