It is actually pretty vague. Here are some statements out of the legal firearms section of the regs.
"Rifles may be used for taking wild animals and birds, except migratory game birds and waterfowl (see Game Species Definitions), and where prohibited by local ordinances (see Local Firearms Ordinances).
Rifles used for deer or bear must be .23 caliber or larger.
Rifles, pistols, and revolvers may be used for hunting crows, except where prohibited by local ordinances (see Local Firearms Ordinances).
Pistols and revolvers firing .22 caliber rimfire ammunition and muzzleloading pistols may be used for small game where .22 rifles are permitted (see Local Firearms Ordinances).
Pistols and revolvers are lawful for deer and bear hunting only in those counties where hunting deer and bear with rifles is lawful. Cartridges used must be .23 caliber or larger and have a manufacturer’s rating of 350 foot-pounds muzzle energy or more."
Notice they cover about all the scenarios except for Pistols other than 22 rimfire.
Here is where I got this:
http://www.dgif.state.va.us/hunting/regulations/