Yes, there have been firearms companies operating in Washington, D.C., although the district has strict gun control laws. One notable example was the Washington Navy Yard, which historically included facilities related to firearms manufacturing and testing. Additionally, some small businesses and shops may sell firearms or related products, but the overall presence of firearms companies is limited due to regulatory constraints.
No.
100-300
No records for this importer of firearms, and they are now closed. Sorry-
100 USD
20-60 USD or so
The FCC in Washington, DC.
10-100 USD or so
You pretty much have it all.
Seldom exceed 100 USD
IIRC, Firearms International was the importer, not maker. ONE such rifle that I can recall was the Bronco.
About 100 USD
50-300 usd