Colt firearms contain steel made Elsewhere. Many of the machines that make them are made Elsewhere. There ARE gunsmiths who make their arms from scratch, including making their own steel and using machines that were made either by them or truly historic pieces.

A flintlock will set you back up to USD 20,000, cheapest about 1,500. French and English gunflints are well thought of, but getting your own from nearby hills will work. Chickenshit makes good saltpeter, but it takes awhile and the neighbors might complain when you start pouring "chamber lye" over your nitrate beds in the backyard. Domestic sulphur and charcoal are easily had, but the best charcoal is stuff you make yourself from willow.

REAL Americans make their OWN firearms.

I am not a REAL American.