Short answer

No replica Speedmaster runs an Omega Calibre 9300. Omega builds that movement in house, and it never leaves the factory in loose form. What the market sells as a "9300 replica" is a case, dial and bracelet built to look like a 44.25 mm Speedmaster Co-Axial Chronograph, fitted with a Seagull ST19, a modified Valjoux/ETA 7750, or a Chinese quartz module. The proportions are close, the function is usually different, and the watch is not serviceable by Omega. Buy the look if the look is what you want. Do not buy it expecting the mechanics.

What the real Calibre 9300 does

Omega's 9300 is an automatic column-wheel chronograph with a vertical clutch, a co-axial escapement, a silicon balance spring and a twin-barrel layout rated at roughly 60 hours of reserve. On the dial it reads as a bi-compax: a 60-minute totalizer at 3 o'clock, a 12-hour totalizer at 9 o'clock, a date window at 6, and a central chronograph seconds hand. No running seconds sub-dial in the classic sense, which is exactly why the layout confuses people who are used to a three-register 7750 watch.

Later versions of the same family earned Master Chronometer certification, which covers both chronometric rate and resistance to magnetic fields up to 15,000 gauss. That is a laboratory test on the whole cased watch, not a spec sheet claim.

What the replica version contains

Builders fake the dial, so they pick whatever movement makes the hand positions line up. That leads to a few common outcomes.

• ST19 manual wind. Smooth pusher feel and a nice column wheel, but hand wound only. If the caseback is solid it is hard to tell, and many owners never wind it enough.
• Asian 7750. Automatic and widely available. The stock layout is running seconds at 9 and 12-hour counter at 6, so builders either move the hands or leave a sub-dial doing the wrong job.
• Quartz. Cheap, accurate and honest about being a fashion piece. Stepping seconds on the chrono hand give it away instantly.

None of these have a co-axial escapement, silicon hairspring, twin barrels or a 60-hour reserve. Most run 38 to 48 hours on a good day.

Where the dial layout usually goes wrong

This is the first thing I look at in photos. On the genuine 9300 the left sub-dial is a 12-hour counter, so it sits still until the chronograph has run for hours. On a lot of copies the left sub-dial is the running seconds, which means it sweeps the moment you pick the watch up. That single behavior tells you more than any close-up of the printing. If a listing shows a third sub-dial, a tri-compax arrangement, or a day-date at 3, the maker copied a different Speedmaster and used the wrong reference.

Checks worth doing on any listing

• Case thickness and crown position. Real 9300 Speedmasters are thick, and thin copies look flat on the wrist.
• Bezel insert alignment at 12 and the spacing of the tachymeter markings.
• Date window position and font. The number should sit level and centered.
• Pusher feel. Mushy or grinding pushers mean the movement was assembled without care.
• End-link fit against the case. Gaps or a wobbly bracelet are the easiest quality tell.
• Lume. Charge the dial for a minute under a lamp and see whether the hands and markers glow to the same brightness.
• Caseback engraving depth and spelling. Faked text is often shallow and slightly oversized.

Service, water and resale

An ST19 or a 7750 can be serviced by a competent independent watchmaker, usually for the price of the watch itself. Water resistance on a replica is a claim, not a test. Gaskets are often dry or missing, and I would not swim with one unless a watchmaker pressure tested it first. Resale value is close to zero, and no authorized service center will touch it. Treat every dollar spent as spent.

Legal and practical notes

Counterfeit watches infringe trademarks and are subject to seizure at the border in many countries, including the United States. Shipping risk falls on the buyer. There is also the ownership side: the watch has no warranty, no parts support and no history. If the appeal is the 9300 layout and the chronograph function, a used genuine Speedmaster or a different bicompax chronograph will give you both, at a much higher price but with something to sell later.

Who this suits

A replica Cal 9300 Speedmaster suits someone who wants the look of a 44 mm two-register Moonwatch on a budget, understands that the movement is generic, and does not plan to swim in it or pass it on. If you expect a column-wheel feel, a 60-hour reserve or real co-axial internals, you will be disappointed, because those parts are not in the box.