OMEGA · Speedmaster Chronoscope and Speedmaster '57

OMEGA 329.30.43.51.03.001 vs OMEGA 332.10.41.51.01.001

7 published specifications differ between these two, and 6 are identical. Every figure below is what the manufacturer states for that reference; nothing is inferred from the other watch.

What differs

Specification	OMEGA Speedmaster Chronoscope 43mm, blue dial329.30.43.51.03.001	OMEGA Speedmaster '57 Co-Axial Master Chronometer Chronograph 40.5mm332.10.41.51.01.001
Case	Steel, 43 mm	Steel, 40.5 mm
Diameter	43 mm	40.5 mm
Lug to lug	48.6 mm	49.64 mm
Lug width	21 mm	20 mm
Dial	Blue	Black
Calibre	OMEGA 9908	OMEGA 9906
Movement notes	Listed by OMEGA as a Master Chronometer certified watch. Total product weight approximately 145 g. No case thickness is published on this product page.	Listed by OMEGA as a Master Chronometer certified watch. Total product weight approximately 134 g.

What is identical

Worth knowing as much as the differences: these are the specifications you cannot use to tell the two apart.

Water resistance: 5 bar (50 metres / 165 feet)
Crystal: Scratch-resistant sapphire crystal with anti-reflective treatment on both sides
Bracelet: Steel
Clasp: Foldover clasp with comfort setting
Movement: Manual-winding
Power reserve: 60 hours

Stated for one, not the other

These rows cannot be compared, because one maker publishes the figure and the other does not. An empty cell is a gap in the manufacturer's documentation, not a gap in the watch — and not a licence to fill it in from the other column.

Thickness	not stated	12.99 mm

What the differences cost you

Each note below follows from the published figures in the tables above — what they mean for intake, for a listing, and for the handover. Nothing here estimates a price or a margin.

These reach different buyers

43 mm on the 329.30.43.51.03.001 against 40.5 mm on the 332.10.41.51.01.001. Diameter is a poor predictor of how a watch actually sits, but it is the field buyers filter on, so the two land in front of different people. Do not let one listing's photographs or copy stand in for the other.

Different movements to verify and to service

The 329.30.43.51.03.001 runs the OMEGA 9908 and the 332.10.41.51.01.001 the OMEGA 9906. Two consequences at intake: the service history that is normal for one calibre is not evidence about the other, and the calibre is the check that catches a movement swapped into the wrong case. Confirm the movement matches the reference rather than assuming it from the dial.

What to check on each

329.30.43.51.03.001

Measure the case height yourself and say that you measured it. OMEGA publishes no thickness for this reference, and borrowing a figure from another Speedmaster is a claim nobody can support.
Confirm the movement is the manual-winding 9908 rather than one of the self-winding calibres used elsewhere in the collection, since the winding behaviour is completely different.
Wind it fully and treat the stop as absolute. With no rotor there is no slipping bridle, and forcing the crown past the end of travel is how mainsprings break.

332.10.41.51.01.001

Wind it from stopped and pay attention to the feel. This is a manual movement, so your fingers are directly on the barrel and the train, and resistance that is uneven or a stop that arrives early is a real finding.
Never force the crown past its stop. A manual mainspring has no slipping bridle to protect it, and a previous owner used to automatics may already have tried.
Note the 60-hour reserve, which is long for a hand-wound chronograph and means a buyer can skip a day without resetting.

Sources

Not affiliated with OMEGA. Specifications are read from each manufacturer's own published documentation on the dates shown and may change; the manufacturer's current documentation governs.