Short answer
The Omega Speedmaster Calibre 9300 is an automatic co-axial chronograph. Replicas sold from China copy the case shape, the dial print, and the two-register layout. Most do not copy the movement. A watch sold as a cal 9300 replica holds a modified Asian 7750 or a Seagull ST19 base. The gear train, the escapement, and the winding system differ from the Omega original.
Genuine calibre 9300 specifications
- Automatic winding, two barrels in series
- Co-axial escapement with a silicon balance spring
- 60-hour power reserve
- 25,200 vibrations per hour, equal to 3.5 hertz
- 54 jewels
- Column wheel and vertical clutch
- Two sub-dials, at 3 and 9 o'clock
- Date window at 6 o'clock
- Case size 44.25 mm on the Speedmaster Co-Axial Chronograph
Where replica versions differ
A Valjoux 7750 base has three registers, at 12, 6, and 9 o'clock. Builders who use that base for a two-register Speedmaster look block the 12 o'clock register with a plate or print a dial that hides it. The plate raises the case height. Genuine cal 9300 Speedmasters run thick, past 16 mm, because of the two barrels and the chronograph works. A 7750 copy sits at 17 mm or more.
The date window is a second tell. Omega put the date at 6 o'clock on cal 9300 Speedmasters. Many copies carry the date at 3 o'clock, which matches the 7750 date wheel with no extra gearing.
The caseback is a third tell. Omega fits a sapphire caseback to cal 9300 Speedmasters, so the movement stays visible. A decorated rotor with laser etching does not change the base caliber.
Inspection points
- Count the sub-dials. Two sub-dials at 3 and 9 o'clock match the cal 9300. Three registers at 12, 6, and 9 point to a 7750.
- Check the date position. 6 o'clock matches the cal 9300 Speedmaster. 3 o'clock does not.
- Measure the case thickness with calipers.
- Run the watch on a timegrapher. 25,200 vph matches the Omega 9300 family. 28,800 vph points to a 7750.
- Start the chronograph. A column wheel with a vertical clutch sends the seconds hand off with no jump. A horizontal clutch, used in the Seagull ST19, makes the hand jump.
- Read the balance. A free-sprung balance with no regulator index matches Omega. A stud and index arm does not.
US law
US law treats counterfeit watches as counterfeit goods, not as replicas. 18 U.S.C. 2320 covers trafficking. US Customs and Border Protection seizes counterfeit watches at ports of entry. A watch with an Omega trademark on the dial and a non-Omega movement is a counterfeit item under that statute. Penalties include fines and prison terms.
What is not known
No public data covers the number of cal 9300 replicas in circulation, the factories that build them, or their failure rates. Sellers label watches with numbers that do not match any Omega caliber code.