I'm getting into this late, but the info from jmc, eightbore and others is spot on. There are a few other shops in the area, but virtually all of them are heavy into black rifles and square pistols, neither of which interest me, but sometimes a good old used gun shows up. Condon and Tony Wilcox are the main dealers in antique and classic stuff, but don't forget Cliff Sofia's CSArmory in Upperville (Rte 50 a few clicks west of Middleburg).
Last year I learned that the late John Appleton's shop in Front royal is still in business, sorta.... As of this summer it was open on Saturdays, 11 a.m. to 2 p..m with Alice tending the counter and telephone. Besides the Martini target and Int'l .22s that John imported in quantity there was still a fair assortment of European doubleguns and smoothbore oddments in three to five figure ranges. I was able to buy a like-new BSA Martini barreled action, a set of Parker-Hale sights and a semi-finished stock for a very fair price, and putting them together is now my winter project. The backroom is said to be a trove of parts in serious need of sorting and labelling, according to one regular customer. There's no website, but you can google the phone number.
