I do not know if google is always your friend and up to date!
The list you have drawn from the search shows in somes cases gun makers which are long out of business.
I try to compile a list with existing gun makers which I know personally and think are worth to mention. Some of them are of course already included in your list. The list is of course not complete.

I do not know who import into the USA. This list does not only include gun makers specialized on bolt action rifles.

Hartmann & Weiss, Hamburg;
Max Ern, Schlebusch Leverkusen
Jens Ziegenhahn, Zella-Mehlis
Heinrich Schiller, Leutershausen
Theo Jung, Lohmar
Gernot Walther, Kochel am See
Thosten Retz, Suhl
Marko Frühauf, Schleusingen
Uwe Holz, Wrangels, former H&W employee
Sebastian Wlodertz, Perleberg; former H&W employee
Reimer Johannsen, Neumünster
Gottfried Prechtl, Birkenau
Harry Baelder, Rickling
Karl Heinz Ritterbusch, Haldenwang
Michael Velser, Nerdlen

Robert