While I am not a lawyer or play one on TV here is what I found under Virginia state law.
Virginia Title 18.2 Chapter 7 has the following definitions:
"Handgun" means any pistol or revolver or other firearm, except a machine gun, originally designed, made, and intended to fire a projectile by means of an explosion of a combustible material from one or more barrels when held in one hand.
"Sawed-off rifle" means a rifle of any caliber, loaded or unloaded, which expels a projectile by action of an explosion of a combustible material and is designed as a shoulder weapon with a barrel or barrels length of less than 16 inches or which has been modified to an overall length of less than 26 inches.
Based on the two definitions I don't see anything that discusses OAL greater than 26" and I don't see any statute that states what dimensions a pistol can have.
Title 18.2-308 has the following:
A. If any person carries about his person, hidden from common observation, (i) any pistol, revolver, or other weapon designed or intended to propel a missile of any kind by action of an explosion of any combustible material; It shall be an affirmative defense to a violation of clause (i) regarding a handgun, that a person had been issued, at the time of the offense, a valid concealed handgun permit.
C. Except as provided in subsection A of §
18.2-308.012, this section shall not apply to:
8. Any person who may lawfully possess a firearm and is carrying a handgun while in a personal, private motor vehicle or vessel and such handgun is secured in a container or compartment in the vehicle or vessel;
Title 18.2-308.01 has the following:
A. The prohibition against carrying a concealed handgun in clause (i) of subsection A of §
18.2-308 shall not apply to a person who has a valid concealed handgun permit issued pursuant to this article. The person issued the permit shall have such permit on his person at all times during which he is carrying a concealed handgun and shall display the permit and a photo identification issued by a government agency of the Commonwealth or by the U.S. Department of Defense or U.S. State Department (passport) upon demand by a law-enforcement officer.
If you can shoot it with one hand then I would say the state's definition would qualify it as a pistol and a valid carry permit would allow it in a vehicle, otherwise it would more than likely need to be unloaded and secured in order to be in a vehicle.
Again, I am not a lawyer and this is not any form of legal advice, just one man's interpretation.