Originally Posted by Loner
Sidecar, Schott makes scope glass in their Rochester plant I believe. USO, Trijicon and
maybe Premeir use it. I don't know if USO uses only US made Schott though.
In the riflescope industry, Schott is a glass material supplier, not lens fabricator. The supplier of the raw glass is really a secondary issue, because most of the cost is in the process of grinding and polishing glass material into lenses. All the major glass material suppliers, like Schott, Hoya, O'Hara, etc., make equivalent quality glasses and distribute them internationally to the companies that fabricate the lenses.
For riflescopes and other high end sport optics, it's typically the optical design and lens fabrication process that determine the optical quality of the end product. In the lens fabrication process, it's primarily surface figure that determines performance and cost. Better optical performance requires a better surface figure which takes more fabrication time and therefore costs more.
It's very likely that all the companies that make scopes in the US buy lenses from the same lens suppliers, who in turn use both on and offshore factories to fabricate the lenses. Regardless of where the lens is fabricated, surface figure is what matters.