This replica Big Bang 1780 44mm places the 301.PM.1780.RX reference in Hublot’s rose gold case with a chronograph movement and dark dial configuration. At 44mm it represents the earlier Big Bang sizing before the collection shifted toward 45mm Unico models, and the three-register chronograph layout gives the dial a busier, more instrument-like character than the skeletonized Unico variants that came later.

Case & Movement Specs

• Case diameter: 44mm
• Case material: 18K rose gold (PM designation)
• Bezel: rose gold with six H-shaped titanium screws
• Crystal: sapphire with AR coating
• Dial: dark with three chronograph subdials
• Strap: rubber with deployant clasp
• Movement: automatic chronograph
• Functions: hours, minutes, running seconds, chronograph (12h/30min/seconds), date

The three-subdial chronograph format places a running seconds counter at 9, a 30-minute register at 3, and a 12-hour totalizer at 6. Date sits at 4:30 via an angled window, maintaining the symmetry of the subdial arrangement.

Caliber Breakdown

Classic Big Bang chronographs from the 301 series use a proven automatic base with a chronograph module, differing from the fully integrated Unico architecture found in newer 4xx references. The modular approach means a reliable, well-understood movement platform. Pushers at 2 and 4 o’clock actuate the chronograph with a mechanical click that confirms engagement. For a different expression of the same precious-metal concept, look at the Unico 441.OX.1180.RX.1704, which uses King Gold in the newer 45mm Unico format. The full Big Bang collection spans both chronograph architectures across multiple case materials.

How It Compares

The 301 series at 44mm feels noticeably different on the wrist compared to a 45mm Unico. One millimeter sounds marginal, but the earlier case design also sits slightly thinner due to the modular movement stack. The rose gold case warms to skin temperature quickly and develops a subtle patina character that King Gold resists. Three chronograph subdials give this dial more visual information density than a skeletonized Unico, which appeals to those who want their complications read at a glance rather than observed through cutaways. This replica Big Bang 1780 44mm captures the original Big Bang chronograph formula in precious metal before the Unico generation changed the game.