The only one I don't see on the list is Purcell's in Purcellville, if you are willing to go for a drive in the country. Not a great stocking selection, but he can order most anything. He competes on price and the owner runs the place. He occasionally has awesome specials depending on what he has ordered.
Been to Mr. Furr in Vienna/Reston. Not much stock, but if you know what you want he can get it and the owner runs it obviously. He even demo'd take down on my new Sig I was picking up from him.
I'd say Loudoun Guns and Virginia Arms are the big "stocking" dealers. A good bit of inventory in both. Prices are a bit more than the non-stocking places for the obvious reasons. LG is run by the owner who is there a fair bit, his cousin is the manager, his wife...you get the idea. Not that familiar with VA, but I have friends that buy there regularly and are happy with the shop. I understand the owner runs it.
BRA - Good range, but I haven't bought a gun there since LG opened in Leesburg. I used to live out in western Loudoun, so it was a hike to get to BRA for higher prices and no selection. They have greatly improved the range under the new ownership and I believe it is worth the money for a nearby indoor facility, so obviously I'm a member. They also allow rifle and shotgun now, where before it was extremely limited.
There is always the
Nation's Gun Show coming up in a few weeks. Chantilly Expo Center on Rte 28 near Rte 50.
If you are looking for outdoor ranges and or clay shooting there are several good places in the area.
Bull Run Park (NVRPA),
Arlington/Fairfax IWLA and
Loudoun IWLA all have clay shooting. The two IWLA chapters also have outdoor rifle pistol ranges out to 100yds.