Info courtesy of m1gunr


So you want to buy a pistol at the age 18 from a private seller? Lets go look at Title 18 USC 922 the section on Unlawful Acts (subsection X)
http://www.nraila.org/federalfirearms.htm#Sec.%20922

which states:
(1) It shall be unlawful for a person to sell, deliver, or otherwise transfer to a person who the transferor knows or has reasonable cause to believe is a juvenile:
(A) a handgun;or
(B) ammunition that is suitable for use only in a handgun.

(5) For purposes of this subsection, the term "juvenile" means a person who is less than 18 years of age.

So the Feds allow you to buy a handgun at 18 from private sellers but according to Washington RCW 9.41.240 you can only carry it on your own property. WRONG because RCW 9.41.060 provides an exception for 9.41.240 as well as 9.41.050 (concealed about your person & loaded in a vehicle). Specifically look at sections 7 & 8 in RCW 9.41.060. Because of this exception you can carry that pistol concealed about your person if you are a member of a gun collector club (think WAC), going to and from the events. If you meet the requirements in section 8 (hiking, hunting, fishing, etc), you may carry that pistol to and from that activity as well.

I am not a lawyer and this is by no means legal advice.

RCW 9.41.240
Possession of pistol by person from eighteen to twenty-one.
Unless an exception under RCW 9.41.042, 9.41.050, or 9.41.060 applies, a person at least eighteen years of age, but less than twenty-one years of age, may possess a pistol only:
(1) In the person's place of abode;
(2) At the person's fixed place of business; or
(3) On real property under his or her control.

RCW 9.41.050
Carrying firearms.
(1)(a) Except in the person's place of abode or fixed place of business, a person shall not carry a pistol concealed on his or her person without a license to carry a concealed pistol.
(b) Every licensee shall have his or her concealed pistol license in his or her immediate possession at all times that he or she is required by this section to have a concealed pistol license and shall display the same upon demand to any police officer or to any other person when and if required by law to do so. Any violation of this subsection (1)(b) shall be a class 1 civil infraction under chapter 7.80 RCW and shall be punished accordingly pursuant to chapter 7.80 RCW and the infraction rules for courts of limited jurisdiction.
(2)(a) A person shall not carry or place a loaded pistol in any vehicle unless the person has a license to carry a concealed pistol and: (i) The pistol is on the licensee's person, (ii) the licensee is within the vehicle at all times that the pistol is there, or (iii) the licensee is away from the vehicle and the pistol is locked within the vehicle and concealed from view from outside the vehicle.
(b) A violation of this subsection is a misdemeanor.
(3)(a) A person at least eighteen years of age who is in possession of an unloaded pistol shall not leave the unloaded pistol in a vehicle unless the unloaded pistol is locked within the vehicle and concealed from view from outside the vehicle.
(b) A violation of this subsection is a misdemeanor.
(4) Nothing in this section permits the possession of firearms illegal to possess under state or federal law.

RCW 9.41.060
Exceptions to restrictions on carrying firearms.
The provisions of RCW 9.41.050 shall not apply to:
(1) Marshals, sheriffs, prison or jail wardens or their deputies, or other law enforcement officers of this state or another state;
(2) Members of the armed forces of the United States or of the National Guard or organized reserves, when on duty;
(3) Officers or employees of the United States duly authorized to carry a concealed pistol;
(4) Any person engaged in the business of manufacturing, repairing, or dealing in firearms, or the agent or representative of the person, if possessing, using, or carrying a pistol in the usual or ordinary course of the business;
(5) Regularly enrolled members of any organization duly authorized to purchase or receive pistols from the United States or from this state;
(6) Regularly enrolled members of clubs organized for the purpose of target shooting, when those members are at or are going to or from their places of target practice;

(7) Regularly enrolled members of clubs organized for the purpose of modern and antique firearm collecting, when those members are at or are going to or from their collector's gun shows and exhibits;

(8) Any person engaging in a lawful outdoor recreational activity such as hunting, fishing, camping, hiking, or horseback riding, only if, considering all of the attendant circumstances, including but not limited to whether the person has a valid hunting or fishing license, it is reasonable to conclude that the person is participating in lawful outdoor activities or is traveling to or from a legitimate outdoor recreation area;

(9) Any person while carrying a pistol unloaded and in a closed opaque case or secure wrapper; or
(10) Law enforcement officers retired for service or physical disabilities, except for those law enforcement officers retired because of mental or stress-related disabilities. This subsection applies only to a retired officer who has: (a) Obtained documentation from a law enforcement agency within Washington state from which he or she retired that is signed by the agency's chief law enforcement officer and that states that the retired officer was retired for service or physical disability; and (b) not been convicted or found not guilty by reason of insanity of a crime making him or her ineligible for a concealed pistol license.

Title 18 USC Section 922 - Unlawful acts (see subsection X)
(1) It shall be unlawful for a person to sell, deliver, or otherwise transfer to a person who the transferor knows or has reasonable cause to believe is a juvenile:
(A) a handgun;or
(B) ammunition that is suitable for use only in a handgun.
(2) It shall be unlawful for any person who is a juvenile to knowingly possess:
(A) a handgun;or
(B) ammunition that is suitable for use only in a handgun.

(3) This subsection does not apply to:
(A) a temporary transfer of a handgun or ammunition to a juvenile or to the possession or use of a handgun or ammunition by a juvenile if the handgun and ammunition are possessed and used by the juvenile:
(i) in the course of employment, in the course of ranching or farming related to activities at the residence of the juvenile (or on property used for ranching or farming at which the juvenile, with the permission of the property owner or lessee, is performing activities related to the operation of the farm or ranch), target practice, hunting, or a course of instruction in the safe and lawful use of a handgun;
(ii) with the prior written consent of the juvenile's parent or guardian who is not prohibited by Federal, State, or local law from possessing a firearm, except:
(I) during transportation by the juvenile of an unloaded handgun in a locked container directly from the place of transfer to a place at which an activity described in clause (i) is to take place and transportation by the juvenile of that handgun, unloaded and in a locked container, directly from the place at which such an activity took place to the transferor or;
(II) with respect to ranching or farming activities as described in clause(i), a juvenile may possess and use a handgun or ammunition with the prior written approval of the juvenile's parent or legal guardian and at the direction of an adult who is not prohibited by Federal, State or local law from possessing a firearm;
(iii) the juvenile has the prior written consent in the juvenile's possession at all times when a handgun is in the possession of the juvenile; and
(iv) in accordance with State and local law;
(B) a juvenile who is a member of the Armed Forces of the United States or the National Guard who possesses or is armed with a handgun in the line of duty;
(C) a transfer by inheritance of title (but not possession) of a handgun or ammunition to a juvenile;or
(D) the possession of a handgun or ammunition by a juvenile taken in defense of the juvenile or other persons against an intruder into the residence of the juvenile or a residence in which the juvenile is an invited guest.
(4) A handgun or ammunition, the possession of which is transferred to a juvenile in circumstances in which the transferor is not in violation of this subsection shall not be subject to permanent confiscation by the Government if its possession by the juvenile subsequently becomes unlawful because of the conduct of the juvenile, but shall be returned to the lawful owner when such handgun or ammunition is no longer required by the Government for the purposes of investigation or prosecution.
(5) For purposes of this subsection, the term "juvenile" means a person who is less than 18 years of age.