The case is one millimeter wider than the original 6BB because it runs on a slightly larger movement, Hamilton’s caliber H-51-Si. This new-ish movement debuted in 2021 with the hand-wound Intra-Matic.
Based on the ETA caliber 7753, it beats at 28,800vph, has a 60-hour power reserve and a silicone balance spring.

The Khaki Pilot Pioneer Mechanical Chrono has an intriguing military history and finally has an eye-catching dial suitable for daily wear on the ground. Aside from the clunky name, this is one of the most underrated watches in Hamilton’s impressive catalog.
Availability and price
While it doesn’t make much sense on a retro-inspired military pilot’s watch, the new steel mesh bracelet option, borrowed from the Intra-Matic, maximizes the blue dial’s visual appeal.
The Hamilton Khaki Pilot Pioneer Mechanical Chrono is available now from Hamilton. It costs $2,195 on a brown leather strap and $2,245 on a steel mesh bracelet.
