In adition to the below quote an 18 yr old can carry open in AZ without a parent as well as purchase a handgun from a private seller.
Right out of Arizona Revised Statutes
13-3102. Misconduct involving weapons; defenses; classification; definitions
A. A person commits misconduct involving weapons by knowingly:
1. Carrying a deadly weapon without a permit pursuant to section 13-3112 except a pocket knife concealed on his person; or
2. Carrying a deadly weapon without a permit pursuant to section 13-3112 concealed within immediate control of any person in or on a means of transportation; or
3. Manufacturing, possessing, transporting, selling or transferring a prohibited weapon, except that if the violation involves dry ice, a person commits misconduct involving weapons by knowingly possessing the dry ice with the intent to cause injury to or death of another person or to cause damage to the property of another person; or
4. Possessing a deadly weapon or prohibited weapon if such person is a prohibited possessor; or
5. Selling or transferring a deadly weapon to a prohibited possessor; or
6. Defacing a deadly weapon; or
7. Possessing a defaced deadly weapon knowing the deadly weapon was defaced; or
8. Using or possessing a deadly weapon during the commission of any felony offense included in chapter 34 of this title; or
9. Discharging a firearm at an occupied structure in order to assist, promote or further the interests of a criminal street gang, a criminal syndicate or a racketeering enterprise; or
10. Unless specifically authorized by law, entering any public establishment or attending any public event and carrying a deadly weapon on his person after a reasonable request by the operator of the establishment or the sponsor of the event or the sponsor's agent to remove his weapon and place it in the custody of the operator of the establishment or the sponsor of the event for temporary and secure storage of the weapon pursuant to section 13-3102.01; or
11. Unless specifically authorized by law, entering an election polling place on the day of any election carrying a deadly weapon; or
12. Possessing a deadly weapon on school grounds; or
13. Unless specifically authorized by law, entering a nuclear or hydroelectric generating station carrying a deadly weapon on his person or within the immediate control of any person; or
14. Supplying, selling or giving possession or control of a firearm to another person if the person knows or has reason to know that the other person would use the firearm in the commission of any felony; or
15. Using, possessing or exercising control over a deadly weapon in furtherance of any act of terrorism as defined in section 13-2301 or possessing or exercising control over a deadly weapon knowing or having reason to know that it will be used to facilitate any act of terrorism as defined in section 13-2301.
B. Subsection A, paragraph 1 of this section shall not apply to a person in his dwelling, on his business premises or on real property owned or leased by that person.
C. Subsection A, paragraphs 1, 2, 3, 7, 10, 11, 12 and 13 of this section shall not apply to:
1. A peace officer or any person summoned by any peace officer to assist and while actually assisting in the performance of official duties; or
2. A member of the military forces of the United States or of any state of the United States in the performance of official duties; or
3. A warden, deputy warden or correctional officer of the state department of corrections; or
4. A person specifically licensed, authorized or permitted pursuant to a statute of this state or of the United States.
D. Subsection A, paragraphs 3 and 7 of this section shall not apply to:
1. The possessing, transporting, selling or transferring of weapons by a museum as a part of its collection or an educational institution for educational purposes or by an authorized employee of such museum or institution, if:
(a) Such museum or institution is operated by the United States or this state or a political subdivision of this state, or by an organization described in 26 United States Code section 170(c) as a recipient of a charitable contribution; and
(b) Reasonable precautions are taken with respect to theft or misuse of such material.
2. The regular and lawful transporting as merchandise; or
3. Acquisition by a person by operation of law such as by gift, devise or descent or in a fiduciary capacity as a recipient of the property or former property of an insolvent, incapacitated or deceased person.
E. Subsection A, paragraph 3 of this section shall not apply to the merchandise of an authorized manufacturer of or dealer in prohibited weapons, when such material is intended to be manufactured, possessed, transported, sold or transferred solely for or to a dealer, a regularly constituted or appointed state, county or municipal police department or police officer, a detention facility, the military service of this or another state or the United States, a museum or educational institution or a person specifically licensed or permitted pursuant to federal or state law.
F. Subsection A, paragraph 1 of this section shall not apply to a weapon or weapons carried in a belt holster that is wholly or partially visible, or carried in a scabbard or case designed for carrying weapons that is wholly or partially visible or carried in luggage. Subsection A, paragraph 2 of this section shall not apply to a weapon or weapons carried in a case, holster, scabbard, pack or luggage that is carried within a means of transportation or within a storage compartment, map pocket, trunk or glove compartment of a means of transportation.
G. Subsection A, paragraph 10 of this section shall not apply to shooting ranges or shooting events, hunting areas or similar locations or activities.
H. Subsection A, paragraph 3 of this section shall not apply to a weapon described in section 13-3101, subsection A, paragraph 8, subdivision (a), item (v), if such weapon is possessed for the purposes of preparing for, conducting or participating in lawful exhibitions, demonstrations, contests or athletic events involving the use of such weapon. Subsection A, paragraph 12 of this section shall not apply to a weapon if such weapon is possessed for the purposes of preparing for, conducting or participating in hunter or firearm safety courses.
I. Subsection A, paragraph 12 of this section shall not apply to the possession of a:
1. Firearm that is not loaded and that is carried within a means of transportation under the control of an adult provided that if the adult leaves the means of transportation the firearm shall not be visible from the outside of the means of transportation and the means of transportation shall be locked.
2. Firearm for use on the school grounds in a program approved by a school.
J. The operator of the establishment or the sponsor of the event or the employee of the operator or sponsor or the agent of the sponsor, including a public entity or public employee, is not liable for acts or omissions pursuant to subsection A, paragraph 10 of this section unless the operator, sponsor, employee or agent intended to cause injury or was grossly negligent.
K. Misconduct involving weapons under subsection A, paragraph 9, 14 or 15 of this section is a class 3 felony. Misconduct involving weapons under subsection A, paragraph 3, 4, 8 or 13 of this section is a class 4 felony. Misconduct involving weapons under subsection A, paragraph 12 of this section is a class 1 misdemeanor unless the violation occurs in connection with conduct that violates section 13-2308, subsection A, paragraph 5, section 13-2312, subsection C, section 13-3409 or section 13-3411, in which case the offense is a class 6 felony. Misconduct involving weapons under subsection A, paragraph 5, 6 or 7 of this section is a class 6 felony. Misconduct involving weapons under subsection A, paragraph 1, 2, 10 or 11 of this section is a class 1 misdemeanor.
L. For the purposes of this section:
1. "Public establishment" means a structure, vehicle or craft that is owned, leased or operated by this state or a political subdivision of this state.
2. "Public event" means a specifically named or sponsored event of limited duration that is either conducted by a public entity or conducted by a private entity with a permit or license granted by a public entity. Public event does not include an unsponsored gathering of people in a public place.
3. "School" means a public or nonpublic kindergarten program, common school or high school.
4. "School grounds" means in, or on the grounds of, a school.