I found something else that could be useful. Again, I'm no lawyer.
§ 18.2-309. Furnishing certain weapons to minors; penalty.
A. If any person sells, barters, gives or furnishes, or causes to be sold, bartered, given or furnished, to any minor a dirk, switchblade knife or bowie knife, having good cause to believe him to be a minor, such person shall be guilty of a Class 1 misdemeanor.
B. If any person sells, barters, gives or furnishes, or causes to be sold, bartered, given or furnished, to any minor a handgun, having good cause to believe him to be a minor, such person shall be guilty of a Class 6 felony. This subsection shall not apply to any transfer made between family members or for the purpose of engaging in a sporting event or activity.
(Code 1950, § 18.1-344; 1960, c. 358; 1975, cc. 14, 15; 1992, c. 487; 1993, c. 855.)
§ 1-13.42. Age of majority.
(a) Unless a different meaning appears from the context:
(1) The words "infant," "child," "minor," "juvenile" or any combination thereof shall be construed to mean a person under eighteen years of age.
(2) When used to mean or include disability because of age, the term "person under disability" shall be construed to mean or include a person under eighteen years of age.
(3) The word "adult" shall be construed to mean a person eighteen years of age or over.
(4) The word "infancy" shall be construed to mean the state of being under eighteen years of age.
(b) For the purposes of all laws of the Commonwealth including common law, case law and statutory law, unless an exception is specifically provided in this Code, a person shall be an adult, shall be of full age and shall reach the age of majority when he becomes eighteen years of age.
(1972, cc. 824, 825.)
It looks like to me that it's only a crime to sell a handgun to a minor and a minor is one who is less than 18. Therefore, it seems to be acceptable to sell a handgun to someone between the ages of 18-20. Hope this helps. MJD