The short answer
No one makes a true copy of the Omega caliber 3320. The real 3320 is an Omega chronograph movement from the co-axial family, built on a Frédéric Piguet base, and the number stamped on the rotor of a replica is a label, not a specification. If a listing advertises "Omega 3320" on a watch that costs a few hundred dollars, you are almost certainly looking at an Asian 7750 clone, a Seagull ST19, or a decorated knockoff. Which one you get matters far more than the number on the box.
What the genuine 3320 actually is
Omega introduced George Daniels' co-axial escapement in 1999, and the chronograph calibers that followed share one architecture with small differences between them. The 3303, 3313 and 3320 sit in the same family. They run at 28,800 vibrations per hour, they are automatics, and they were used in the De Ville Co-Axial Chronograph line from the early 2000s.
Two details matter when you check a watch. First, the balance is free-sprung, so there is no regulator arm with a plus and minus scale sitting over it. Second, the escapement is the whole point of the movement, and it is not something a budget factory reproduces.
Why "3320" shows up on fakes at all
Caliber numbers are search terms. Sellers know that buyers type "Omega 3320" before they type "replica De Ville chronograph," so the number gets attached to listings that have nothing to do with it. I have seen the same case described as a 3313, a 3320 and an 1861 depending on the week.
What is usually inside
- Asian 7750. A clone of the Valjoux 7750. Automatic, 28,800 vph, cam-actuated chronograph, 25 jewels. It works, it is serviceable, and it winds with a noticeable rotor whirr.
- Seagull ST19. Hand-wound, column wheel, 21,600 vph. Smooth pushers, no rotor, thinner case. Common in manual chronograph builds.
- Decorated junk. Stamped plates, painted perlage, fake jewels. Usually quartz underneath.
How to check a watch sold as a 3320
- Open the caseback, or ask for a photo of the movement with the back off. A refusal is an answer.
- Look for the regulator. A free-sprung balance has none. A visible regulator arm means it is not a co-axial Omega caliber.
- Read the rotor text. Genuine engraving is crisp, aligned to the curve of the rotor, and matches the caseback.
- Time it. 28,800 vph on a timegrapher is a 7750 pattern. 21,600 vph means a Seagull.
- Listen to the chronograph start. A 7750 engages with a firm clunk and a small jump of the seconds hand. A column wheel movement is smooth and quiet.
What to expect at each price
Below roughly $200 you get the decorated-junk tier, or a quartz chronograph with fake subdials. Between $250 and $600, the good Asian 7750 builds live here, and this is where most buyers should sit if they want a working chronograph. Above that, you are paying for case finishing, sapphire and lume, not for a different movement. Nobody at any price is shipping you a real 3320, because the movement alone costs more than the whole watch.
Bottom line
Treat "Omega 3320" in a replica listing as decoration. Judge the watch on the movement that is actually there, whether the chronograph works, and whether the seller will show it to you. A clean Asian 7750 with good case work beats a vague claim about a caliber that was never in the watch.