I've noticed that some Seamaster Planet Ocean models have "co-axial / master chronometer" on their dials while the Seamaster 300s have "master co-axial / chronometer" on theirs. Is there a difference? Are the 300s METAS certified?

 

Hello Sir the difference from what I have been told is the 300’s did not go through metas and the 8400 movement is what it is numbered due to no date function. The new PO’s are metas certified.

 

The "Master Co-axial" designation also indicates that the watch is anti-magnetic beyond 15,000 Gauss (well past the stated capacity of most other anti-magnetic watches, such as the Rolex Milgauss). I'm not sure whether the "Master Chronometer" METAS designation automatically includes the anti-magnetic feature or not.

 

It does. Part of METAS testing is exposing first the movement, then the assembled watch to a 15,000 gauss (1.5T) field to verify it does not deviate more than 5 sec/day. The new 300s are included in this standard.

 

By entering the reference number, serial number and access code found on the Master Chronometer card into the 'Access my Test Results' section on the Omega website, you can see the tests performed and results for your watch.

My SM300:

 

Nice! I wish I could find out my test results ... I have the same watch (SM300 MC), but it doesn't have the Master Chronometer card for some reason - I think it was one of the earliest ones manufactured. I've had it for over two years already, and it's always run about +12 seconds per day.

 

I'd get it serviced, or at least regulated. +12s/day is outside the spec (which is 0 to +6 s/day).

 

The SM300 MC is not METAS certified as it is a Master Co-axial Chronometer, not a Co-axial Master Chronometer. Confusing, I know.

 

The way I understand:

A. "Co-axial" - Watch features Co-axial escapement

B. "Master" - Omega's terminology for their amagnetic watches, but not necessarily METAS certified.

C. "Chronometer" - COSC certified movement (no watch case), no results online

D. "Master Chronometer" - METAS certified watch (with movement inside) with test results available online. Note: movement is COSC certified prior to METAS testing. METAS testing includes clock precision, resistance to 15,000 Gauss magnetism and water resistance in accordance to depth rating.


Hence,

Co-axial / Master Chronometer = A + D

Master Co-axial / Chronometer = A + B + C

Speedmaster Professional = None of the above

 

And a Quartz is more accurate than all

 

Wtf? So to clarify
1. MCo-aC is not METAS certified but antimagnetic
2. Co-aMC is METAS certified but not antimagnetic

Is there a METAS certified antimagnetic movement that’s a Master Co-axial Master Chronometer?

 

Go to the omega website, select Watchfinder, (link here) https://www.omegawatches.com/watchfinder/ then choose your spec, maybe aqua terra or moonwatch, need to decide exact requirements ie how deep for water etc...

 

If it is METAS certified, the watch is anti-magnetic by default, i.e. since testing for resistance to 15,000 Gauss is part of the METAS testing.

 

Yes, and from how I learned it they are pretty much exactly the same thing but the METAS certificatation just wasn’t in place yet for the Master Co-axial Chronometers, even though they would pass the certification.

 

If timekeeping is worse than what Omega promises (look it up in your booklet), you can get it regulated under warranty. I did this with my Speedmaster around 6-7 months after getting it. Came back a lot less inaccurate

 

I'll send it out right after the holidays.

 

Yet mine is the most accurate mechanical watch I own.

 

What city are you in? You can always send it to a boutique that has a tech and they’ll regulate it. Happy to help further...

 

Metas is anti magnetic and 0-6seconds a day.

 

I'm in southeast Michigan. There's a boutique in Troy, at the Somerset Collection mall. Great folks there - but no tech support available on site. They can send it out to Seattle, though.

 

If you like contact the King of Prussia boutique in Pa., mail it there and I’ll happily test and regulate it for you.