AFAIK, there isn't one.
As far as firearms? Taurus and IMBEL are the big manufacturers there.
a couple or so
Many firearms manufacturers are owned and operated within the US. Among the more prominent manufacturers are Colt, Kimber, Springfield Armory, Bushmaster, Browning, Winchester, Marlin, Mossberg, Remington, etc.
You will have to be more specific... there are a lot of firearms companies and manufacturers called "Keystone". Got a city/state where they operated? Anything?
colt remington smith & wesson mossberg
All firearms are stamped with the name of maker and serial number.
Other than Savage Arms, which firearms manufacturers currently make rifles chambered in 17 Mach 2? Thank you. This is how I tried to configure the question, but the site would not let me ask it in this configuration.
DPMS/Panther Arms is owned by The Freedom Group which owns a wide variety of firearms and ammunition manufacturers including Bushmaster, Remington, H&R, etc...
They were produced by German firearms manufacturers, like Karabiner, who created and produced the Kar98k - or Mauser - rifle.
Eastern Arms was a Sears Roebuck trade name. Manufacturers included Meriden Firearms, Iver Johnson A&C, Stevens/Savage Arms, and Crescent Firearms.
Probably not much to find. It would have been made by one of the larger firearms manufacturers and marked with the Spiegel name. I have never seen a cross-reference to match Spiegel models to any manufacturers' models. Someone who is very familiar with firearms might be able to recognize it.