I'm not surprised. Carbon manganese (CMn) alloys like Managaloy were a significant development. Strength was much higher than hi-tensile steel and closer to chromium-molybdenum (CrMo). Consequently, CMn tubes were almost as thin as CrMo with little weight or resiliency penalty. However, they did not require the close temperature regulation and highly skilled brazers that CrMo did. They could be brazed using more efficient production methods, which helped to bring the cost of butted framesets down into the lower middle price range. It;s got aluminum rims and mostly aluminum components, so I'd expect something in the 25-26 lb range.

BTW, I have one of those water bottles too. They're worth good worry to owners of AX equipped bicycles.