Here's the info that I was able to gather from a respected source:
Burris - Their high-end scopes are manufactured in the US, but I believe that the glass is sourced from Japan. They have gradually outsourced their complete line of lower priced scopes,like the Fullfield II) from Asia since their takeover by Beretta. So, some Asian made scopes from an American-named company that's owned by the Italians! Go figure
Leupold - They claim that all of their riflescopes are manufactured in the US, but some folks have their doubts about their discount store "Rifleman" line. All of their "Golden Ring" and MK4 scopes are manufactured in their plant in Oregon, but they've been VERY closed mouthed as to the origin of their glass. Rumor has it that their high-end lines use Japanese glass, while their less expensive models use glass from other Asian,Chinese?) sources.
Nightforce - Many Japanese made component parts sourced from the former Hakko organization, with very high quality Japanese glass, reportedly from the Optical Light Co. one of the worlds foremost lens producers who make lenses for some of the finest cameras available in the world. NF scopes are finish assembled and serviced at their facilities in Idaho for the US market and,the last I heard) in Australia for the Pacific market.
U S Optics - Excellent custom made scopes manufactured here in the USA. They claim to make their own lenses but rumor has it that it's originally sourced from Japanese lens companies. I couldn't say for sure on that.
Zeiss - Their Conquest line is assembled in a Zeiss factory here in the US from Zeiss supplied parts. Probably most from Germany, but possibly also from Portugal. Rumor has it that the lenses come from the same German glass supplier but are of a lower quality than what goes into their high-end German manufactured models.
I don't claim to be the final authority on this stuff and if anyone has conclusive evidence to the contrary please correct me
